Contact vs Field Forces: What Is the Difference?

A contact force exists only while two objects are touching: the normal force, friction, tension, spring and buoyant forces. A field force acts across empty space, and the AP framework calls it a noncontact force, modeled by a field. In AP Physics 1 the only one is gravity.

AP Physics: Unit 2 (topics 2.2 Forces and Free-Body Diagrams, 2.3 Newton's Third Law, 2.6 Gravitational Force). The current AP framework's own terms are contact force and noncontact force. AP Physics 1 EK 2.2.A.2 states that contact forces describe the interaction of an object or system touching another object or system and are macroscopic effects of interatomic electric forces. EK 2.6.A.2 states that a field models the effects of a noncontact force exerted on an object at various positions in space, and EK 2.6.A.2.i defines the gravitational field magnitude as the ratio of the gravitational force on a test object to that object's mass. The Topic 2.3 boundary statement limits interaction between objects or systems at a distance to gravitational forces in AP Physics 1 and admits gravitational, electric and magnetic forces in AP Physics 2. The phrase field forces appears once across all four Course and Exam Descriptions, in the AP Physics 2 Unit 10 overview narrative and in no essential knowledge statement; long range force and action at a distance appear in none of the four. AP Physics 2 EK 10.1.A.4 calls contact forces nonfundamental, and EK 10.1.B.2 and EK 10.1.B.3 compare the gravitational and electrostatic magnitudes. Unit 2 carries 18 to 23 percent of the AP Physics 1 multiple-choice section; AP Physics 2 Unit 10 carries 15 to 18 percent over about 14 to 21 class periods.

The distinction, and the word the CED actually uses

Two ways for one object to push or pull another.

Contact. EK 2.2.A.2: contact forces describe the interaction of an object or system touching another object or system, and are macroscopic effects of interatomic electric forces. Stop touching and the force is gone the same instant.

Noncontact. EK 2.6.A.2: a field models the effects of a noncontact force exerted on an object at various positions in space. No touching required, and no medium either. Earth pulls on a satellite across 400 km of nothing.

Most textbooks call the second family field forces, which is why you searched for that phrase, and it is a perfectly good name. It is not the name the current AP framework uses in its required content, and section three below sets out exactly which words each Course and Exam Description does use, because a free-response answer written in the framework's vocabulary reads as fluent and one written in a different vocabulary does not.

The useful test is not philosophical. Ask whether the two objects are in physical contact at the instant in question. If they are, the interaction can be a contact force. If they are not, any force between them must be a noncontact one, and in AP Physics 1 that leaves exactly one candidate.

The glossary defines the first family at contact force and the field idea at gravitational field. This page is about the boundary between them, the one place it genuinely matters on an exam, and the reason the boundary is less fundamental than it looks.

Contact vs noncontact, side by side

	Contact force	Noncontact, or field, force
The AP framework's term	Contact force (EK 2.2.A.2)	Noncontact force (EK 2.6.A.2); at a distance (Topic 2.3 boundary)
Touching required	Yes, always	No
Range	Zero. It exists only during contact	Unlimited in principle, weakening with distance
Is it fundamental	No. AP Physics 2 EK 10.1.A.4 calls contact forces nonfundamental	Yes, for gravitational, electric and magnetic interactions
What it is made of underneath	Macroscopic effects of interatomic electric forces (EK 2.2.A.2)	Nothing underneath. This is the bottom layer
How you find its size	From Newton's laws. There is no lookup formula	From a formula: $\lvert \vec{F}_g \rvert = \frac{Gm_1m_2}{r^2}$ , or $F_g = mg$ near Earth
Direction	Set by the geometry of the surfaces	Set by the line joining the two centers of mass (EK 2.6.A.1.ii)
Can it be zero while the objects are close	Yes, the instant contact is lost	No. It weakens with distance and never switches off
Modeled by a field	No	Yes, and that is what a field is for
Obeys Newton's third law	Yes	Yes, identically
In AP Physics 1	Normal, friction, tension, spring, buoyant, drag	Gravitational, and nothing else
Added in AP Physics 2	Nothing new in kind	Electric and magnetic

The row about how you find the size is the one that changes how you work. A noncontact force comes with an equation you can evaluate before you know anything about the motion. A contact force does not, and never will, because its value is whatever the situation demands.

The terminology, checked against all four CEDs

Different courses and different textbooks call this family different things, and the names are not interchangeable in a marked answer. Here is what the four current Course and Exam Descriptions, all Effective Fall 2024, actually contain.

Term	Where it appears
Contact force	AP Physics 1 EK 2.2.A.2, and AP Physics 2 EK 10.1.A.4
Noncontact force	AP Physics 1 EK 2.6.A.2, in the sentence defining what a field models
At a distance	The Topic 2.3 boundary statement, which limits interaction between objects or systems at a distance
Field force	Once, in prose, in the AP Physics 2 Unit 10 overview, which says the unit introduces students to the model of field forces. It appears in no essential knowledge statement
Long range force	Nowhere in any of the four
Action at a distance	Nowhere in any of the four

So the safe usage is this. Write contact force and noncontact force when you need the two categories, because those are the words the required content uses. Write at a distance when you are describing the interaction rather than naming a category, because that is the Topic 2.3 boundary statement's phrase. Field force is understood and is not wrong; it simply is not a term the framework leans on, and it appears exactly once across roughly 850 pages of course description.

One more piece of vocabulary, because it is easy to blur. A field is not a force. EK 2.6.A.2 says a field models the effects of a noncontact force exerted on an object at various positions in space. The field is the map; the force is what a particular object feels when it is standing on the map. That is why the gravitational field has units of N/kg and a force has units of N, and why EK 2.6.A.2.i defines the field magnitude as the ratio of the gravitational force exerted on a test object to the mass of that test object.

The case that separates them: a ball in flight

Throw a ball straight up. Three moments, and the two families behave completely differently across them.

Moment	Contact forces on the ball	Noncontact forces on the ball	Net force
In the hand, being pushed up	The hand's push, large and upward	Gravity, $mg$ downward	Upward and large
Just after the ball leaves the hand	None	Gravity, $mg$ downward	$mg$ downward
At the top of the flight, momentarily at rest	None	Gravity, $mg$ downward	$mg$ downward

Row two is where the standard error lives. Students draw an upward arrow on the flying ball and label it the force of the throw, and it is not a force at all. Contact has ended, so every contact force on the ball has ended with it, instantly and completely. What the throw gave the ball was velocity, and velocity does not need a force to keep it, which is Newton's first law: EK 2.4.A.3 says that if the net force exerted on a system is zero, the velocity of that system will remain constant.

Row three is the second error, and it is the mirror of the first. At the top the ball is not moving, so people delete the force. Gravity is a noncontact force and nothing about the ball's speed changes it. Zero velocity and zero acceleration are unrelated conditions.

Compare that with the noncontact column, which is the same three words in all three rows. Gravity does not care whether anything is touching the ball, how fast it is going or which direction it is heading. Its magnitude changed by an unmeasurable amount over the 0.60 m of the throw, which is exactly the situation EK 2.6.B.1 describes: if the gravitational force between two systems' centers of mass has a negligible change as their relative position changes, the gravitational force can be considered constant at all points between the initial and final positions.

The drawing rules for all of this belong to how to draw a free-body diagram.

Contact forces are electric underneath, so the split is a convenience

This is the part that makes the two categories worth understanding rather than memorizing, and both algebra-based CEDs state it.

EK 2.2.A.2 says contact forces are macroscopic effects of interatomic electric forces. AP Physics 2 EK 10.1.A.4 spells out why the shortcut exists: electric forces are responsible for some of the macroscopic properties of objects in everyday experiences, but the large number of particle interactions that occur make it more convenient to treat everyday forces in terms of nonfundamental forces called contact forces, such as normal force, friction, and tension.

Read that carefully. Contact forces are noncontact forces, at a range so short that nothing ever actually touches. When you press a book, the electrons in your fingertips repel the electrons in the cover across a gap far too small to see, and calling the result a contact force is a bookkeeping decision that saves you from tracking $10^{23}$ separate electric interactions.

Which explains something otherwise strange. A table holds a book up against the gravitational pull of the entire Earth, using nothing but the electric repulsion in a thin layer of atoms. It can do that because the electric interaction is enormously stronger than the gravitational one at the same separation, by a factor worked out in the third example below. AP Physics 2 EK 10.1.B.2 puts it in course language: for any two objects that have mass and electric charge, the magnitude of the gravitational force is usually much smaller than the magnitude of the electrostatic force. EK 10.1.B.3 then explains why gravity nevertheless runs the solar system: gravitational forces dominate at larger scales even though they are weaker than electrostatic forces, because systems at large scales tend to be electrically neutral.

So the honest statement of the categories is not that there are two kinds of force in nature. It is that there is one short-range interaction we repackage as contact and one long-reach interaction we keep at arm's length, and the repackaging is done for our convenience.

What the field model buys you, and why the CED introduces it with gravity

A noncontact force poses a question a contact force does not. If nothing is touching the object, what tells it how hard to be pulled?

The answer is the field, and EK 2.6.A.2 is the definition: a field models the effects of a noncontact force exerted on an object at various positions in space. Instead of asking about a pair of objects each time, you attach a number to every point in space and then any object placed there reads it off.

EK 2.6.A.2.i gives the gravitational case precisely: the magnitude of the gravitational field created by a system of mass $M$ at a point in space is equal to the ratio of the gravitational force exerted by the system on a test object of mass $m$ to the mass of the test object. The CED lists the derived equation:

\lvert \vec{g} \rvert = \frac{\lvert \vec{F}_g \rvert}{m} = G\frac{M}{r^2}

Two consequences that get tested.

First, units. Divide a force by a mass and you get N/kg, and the AP Physics 1 equation sheet prints both $g = 9.8\ \text{m/s}^2$ and $g = 9.8\ \text{N/kg}$ in the constants box as separate lines, because the same number is doing two jobs. EK 2.6.A.2.ii ties them together: if the gravitational force is the only force exerted on an object, the observed acceleration of the object in m/s squared is numerically equal to the magnitude of the gravitational field strength in N/kg at that location.

Second, the field belongs to the source, not to the object. Moving a heavier object to the same spot does not change the field there; it changes the force that object feels, and the field is the ratio that survives. That is why a field can be drawn once on a diagram and used for every object placed in it.

One value to be careful with. EK 2.6.B.2 states that near the surface of Earth the strength of the gravitational field is $g \approx 10\ \text{N/kg}$ , and a Topic 1.3 boundary statement says the exam will use $g \approx 10\ \text{m/s}^2$ wherever a numerical value is required, while adding that students will not be penalized for correctly using the more precise commonly accepted values of $g = 9.81\ \text{m/s}^2$ or $g = 9.8\ \text{m/s}^2$ . The Table of Information prints 9.8. Every number on this page uses 9.8, and is g 9.8 or 10 covers what that choice costs you.

Where it costs a mark

Drawing a force of the throw, a force of the push or a force of motion on an object in flight. No contact, no contact force. This is a standard free-body-diagram error, and it comes straight from misreading which family is acting.
Deleting gravity from a diagram at the top of a trajectory or at the instant of release. A noncontact force does not depend on the object's speed, so gravity has the same value at every point of the flight.
Reaching for a formula to find a contact force. There is no printed equation for the normal force or for tension on any of the four sheets, because their values depend on the geometry and the acceleration. Write the second law and solve. The friction relation $\lvert \vec{F}_f \rvert \leq \lvert \mu \vec{F}_N \rvert$ is a limit rather than a value, and it consumes a normal force you had to find some other way.
Calling a field a force. EK 2.6.A.2 makes the field a model of the effects of a force. The field has units of N/kg, and writing that the gravitational field on a 5 kg mass is 49 N confuses the two.
Assuming a noncontact force needs a medium. It does not. Gravity acts across vacuum, which is how orbits work.
Writing that contact forces are fundamental and field forces are not. It is the other way round. AP Physics 2 EK 10.1.A.4 explicitly calls contact forces nonfundamental.
Treating air resistance as a noncontact force. Air touches the object, so drag is a contact force. The appendix's list of default modeling assumptions for AP Physics 1 says air resistance is negligible unless a question states otherwise, so most of the time it is not on the diagram at all, and when it is, it is in the contact column.
Using electric or magnetic forces in an AP Physics 1 answer. The Topic 2.3 boundary statement limits interaction between objects or systems at a distance to gravitational forces in AP Physics 1, and adds that in AP Physics 2 gravitational, electric, and magnetic forces may be considered.

Which forces are which, by course, and what the sheets print

AP Physics 1. Contact: the normal force, static and kinetic friction, tension, the spring force, and the buoyant and drag forces from a fluid. Noncontact: gravitational, and nothing else. That is not a summary of the usual list, it is the Topic 2.3 boundary statement, which says the interaction between objects or systems at a distance is limited to gravitational forces in AP Physics 1.

AP Physics 2. The same contact forces, plus electric and magnetic forces in the noncontact column, per the same boundary statement. Unit 10, Electric Force, Field, and Potential, is where the second field is introduced, and it carries 15 to 18 percent of the AP Physics 2 multiple-choice section over about 14 to 21 class periods.

On the sheets, the asymmetry between the two families is visible at a glance. The AP Physics 1 sheet prints the noncontact force in full, $\lvert \vec{F}_g \rvert = \frac{Gm_1m_2}{r^2}$ , along with the constants $g = 9.8\ \text{m/s}^2$ and $g = 9.8\ \text{N/kg}$ . For contact forces it prints the spring force $\vec{F}_s = -k\Delta\vec{x}$ , which is a model rather than a general rule, and the friction inequality $\lvert \vec{F}_f \rvert \leq \lvert \mu \vec{F}_N \rvert$ , which caps a force rather than giving it. There is no line for the normal force and no line for tension anywhere on any of the four sheets, and there could not be one, because their values are set by the arrangement of the problem. The near-Earth weight $F_g = mg$ is a derived equation listed under EK 2.6.A.3 rather than a printed one; you write it yourself. The full AP Physics 1 sheet is here and the AP Physics 2 sheet is here.

Where this sits on the exam: Topic 2.2 Forces and Free-Body Diagrams defines contact forces, and Topic 2.6 Gravitational Force introduces the field and the word noncontact. Both are in Unit 2, which carries 18 to 23 percent of the AP Physics 1 multiple-choice section.

A thrown ball: the contact force vanishes and the noncontact force does not

A 0.30 kg ball is thrown straight up. The hand accelerates it uniformly from rest through 0.60 m and releases it at 12 m/s. Find the force the hand exerts during the throw, then list every force on the ball just after release and find its acceleration there. Compare the two families across the release instant.

Declare the convention: positive is upward, and the ball is the system, so the hand and Earth are both outside it.
Acceleration during the throw, from $v^2 = v_0^2 + 2a\Delta y$ with $v_0 = 0$ : $a = v^2/(2\Delta y) = (12\ \text{m/s})^2/(2 \times 0.60\ \text{m}) = 144/1.2 = 120\ \text{m/s}^2$ upward.
Weight of the ball, unchanged throughout: $F_g = mg = (0.30\ \text{kg})(9.8\ \text{m/s}^2) = 2.94\ \text{N}$ downward. This is the noncontact force.
Second law during the throw, with two forces on the ball: $F_{\text{hand}} - F_g = ma$ , so $F_{\text{hand}} = ma + mg = (0.30)(120) + 2.94 = 36 + 2.94 = 38.94\ \text{N}$ upward. This is the contact force.
Now cross the release instant. Contact ends, so $F_{\text{hand}}$ goes from 38.94 N to exactly zero, with nothing in between. Nothing at all happens to $F_g$ , which is still 2.94 N downward.
Forces on the ball just after release: gravity, and nothing else. Air resistance is neglected under the AP Physics 1 default modeling assumption that air resistance is negligible.
Acceleration just after release: $a = F_{\text{net}}/m = (-2.94\ \text{N})/(0.30\ \text{kg}) = -9.8\ \text{m/s}^2$ , that is 9.8 m/s squared downward. The mass cancels, as EK 2.6.A.2.ii says it must when gravity is the only force.
Check the size of the drop. The net force falls from $38.94 - 2.94 = 36\ \text{N}$ upward to $2.94\ \text{N}$ downward, a reversal of direction and a factor of about 12 in magnitude, all of it caused by one contact force ending.

The hand exerts 38.94 N upward during the throw, and after release the ball has exactly one force on it, its 2.94 N weight, giving 9.8 m/s squared downward. There is no upward force on a rising ball. The contact force switched off completely at release while the noncontact force did not flinch, and drawing a leftover force of the throw on the flying ball is the error this example exists to kill.

The gravitational force you are not allowed to ignore, and the one you are

A 2.0 kg book rests on a table. Find the gravitational force Earth exerts on it, then find the gravitational force a 70 kg person standing 0.50 m away exerts on it, using $G = 6.67 \times 10^{-11}\ \text{N} \cdot \text{m}^2/\text{kg}^2$ and treating both as point masses at that separation. Express the second as a fraction of the first and say what it tells you about noncontact forces.

Declare the convention: magnitudes only, since the two forces point in different directions and only their sizes are being compared.
Earth on book, using the near-Earth form: $F_g = mg = (2.0\ \text{kg})(9.8\ \text{m/s}^2) = 19.6\ \text{N}$ .
Person on book, using the general form from EK 2.6.A.1: $\lvert \vec{F}_g \rvert = \frac{Gm_1m_2}{r^2}$ with $m_1 = 2.0\ \text{kg}$ , $m_2 = 70\ \text{kg}$ and $r = 0.50\ \text{m}$ .
Numerator: $Gm_1m_2 = (6.67 \times 10^{-11})(2.0)(70) = (6.67 \times 10^{-11})(140) = 9.338 \times 10^{-9}$ .
Denominator: $r^2 = (0.50)^2 = 0.25\ \text{m}^2$ .
Divide: $F = (9.338 \times 10^{-9})/(0.25) = 3.74 \times 10^{-8}\ \text{N}$ .
Ratio: $(3.74 \times 10^{-8})/(19.6) = 1.9 \times 10^{-9}$ , about two parts in a billion.
Interpret. The noncontact force from the person is genuinely there, at every instant, with no contact of any kind, and it is nine orders of magnitude below the threshold of anything the problem cares about. This is why introductory models drop every gravitational interaction except the one with Earth. College Board's appendix says the same thing about the solar system: when modeling Earth, most often only gravitational effects from the Sun are considered, and even tidal effects from the Moon are only considered after introductory courses.

Earth pulls the book with 19.6 N; the person 0.50 m away pulls it with 3.74 x 10 to the power minus 8 N, about 2 parts in a billion of the first. A contact force is either there or not there. A noncontact force is always there and is usually negligible, and knowing which of those two statements applies is what tells you whether an arrow belongs on the diagram.

Why a table can beat the whole Earth: comparing the two fundamental forces

Two protons sit $1.0 \times 10^{-10}\ \text{m}$ apart, roughly an atomic spacing. Using the AP sheet values $k = 9.0 \times 10^9\ \text{N} \cdot \text{m}^2/\text{C}^2$ , $e = 1.60 \times 10^{-19}\ \text{C}$ , $G = 6.67 \times 10^{-11}\ \text{N} \cdot \text{m}^2/\text{kg}^2$ and $m_p = 1.67 \times 10^{-27}\ \text{kg}$ , find the electrostatic force and the gravitational force between them and take the ratio.

Declare the convention: magnitudes only. Both forces act along the line joining the two protons, the electric one repulsive and the gravitational one attractive.
Electrostatic force: $F_E = k\frac{q_1q_2}{r^2} = (9.0 \times 10^9)\frac{(1.60 \times 10^{-19})^2}{(1.0 \times 10^{-10})^2}$ .
Numerator: $(1.60 \times 10^{-19})^2 = 2.56 \times 10^{-38}\ \text{C}^2$ . Denominator: $(1.0 \times 10^{-10})^2 = 1.0 \times 10^{-20}\ \text{m}^2$ .
Divide and multiply: $(2.56 \times 10^{-38})/(1.0 \times 10^{-20}) = 2.56 \times 10^{-18}$ , then $(9.0 \times 10^9)(2.56 \times 10^{-18}) = 2.30 \times 10^{-8}\ \text{N}$ .
Gravitational force: $F_G = G\frac{m_1m_2}{r^2} = (6.67 \times 10^{-11})\frac{(1.67 \times 10^{-27})^2}{1.0 \times 10^{-20}}$ .
Numerator: $(1.67 \times 10^{-27})^2 = 2.789 \times 10^{-54}\ \text{kg}^2$ . Divide by $1.0 \times 10^{-20}$ to get $2.789 \times 10^{-34}$ .
Multiply: $(6.67 \times 10^{-11})(2.789 \times 10^{-34}) = 1.86 \times 10^{-44}\ \text{N}$ .
Ratio: $F_E/F_G = (2.30 \times 10^{-8})/(1.86 \times 10^{-44}) = 1.2 \times 10^{36}$ .
Notice that the separation cancelled. Both forces go as $1/r^2$ , so the ratio is the same at any distance, and the comparison is a statement about the two interactions rather than about atomic spacing.

Electrostatic 2.30 x 10 to the power minus 8 N, gravitational 1.86 x 10 to the power minus 44 N, a ratio of about 1.2 x 10 to the power 36. That number is why a few atomic layers of tabletop can hold a book up against the pull of an entire planet: the contact force is electric underneath, and the electric interaction outmatches the gravitational one by 36 orders of magnitude between the same pair of particles. AP Physics 2 EK 10.1.B.3 supplies the other half of the story, that gravity still dominates at large scales because large systems tend to be electrically neutral, so the enormous electric forces cancel and the feeble gravitational ones do not.

Frequently asked questions

What is the difference between a contact force and a field force?

A contact force exists only while the two objects are physically touching, and it disappears the instant contact ends. A field force acts across a distance with nothing in between, so it does not need touching and does not need a medium. The current AP framework calls the second family noncontact forces rather than field forces: AP Physics 1 EK 2.6.A.2 says a field models the effects of a noncontact force exerted on an object at various positions in space. Contact forces in the course are the normal force, friction, tension, spring forces and the buoyant and drag forces from a fluid. In AP Physics 1 the only noncontact force is gravity; AP Physics 2 adds electric and magnetic forces.

Does the AP Physics CED use the term field force?

Barely. Across all four current Course and Exam Descriptions the phrase field forces appears once, in the AP Physics 2 Unit 10 overview, which says the unit introduces students to the model of field forces. It appears in no learning objective, no essential knowledge statement and no boundary statement. The terms the required content uses are contact force, in AP Physics 1 EK 2.2.A.2, and noncontact force, in EK 2.6.A.2. The Topic 2.3 boundary statement describes the category as interaction between objects or systems at a distance. The phrases long range force and action at a distance appear nowhere in any of the four. Field force is not wrong, but noncontact force is the word the framework marks against.

Are contact forces really contact, or are they electric?

They are electric, and both algebra-based CEDs say so. AP Physics 1 EK 2.2.A.2 describes contact forces as macroscopic effects of interatomic electric forces, so nothing at the atomic level is actually touching: electrons in one surface repel electrons in the other across a gap far too small to see. AP Physics 2 EK 10.1.A.4 explains why the shortcut exists, saying that the large number of particle interactions makes it more convenient to treat everyday forces in terms of nonfundamental forces called contact forces, such as normal force, friction, and tension. So contact is a bookkeeping category rather than a category in nature, and it saves you from tracking an unmanageable number of separate electric interactions.

Is gravity the only noncontact force in AP Physics 1?

Yes, and the CED says so rather than leaving it to be inferred. The Topic 2.3 boundary statement reads that the interaction between objects or systems at a distance is limited to gravitational forces in AP Physics 1, and adds that in AP Physics 2, gravitational, electric, and magnetic forces may be considered. So on an AP Physics 1 free-body diagram, the only arrow that can be drawn without something touching the object is the gravitational force. Every other arrow requires you to name the thing in contact, which is a useful checking habit: for each force you draw, either say what is touching the object or say that it is gravity.

Is a field the same thing as a force?

No, and confusing them costs marks on units alone. A field is a model: AP Physics 1 EK 2.6.A.2 says a field models the effects of a noncontact force exerted on an object at various positions in space. It assigns a value to every point in space, and any object placed at a point then experiences a force that depends on both the field and the object. EK 2.6.A.2.i gives the gravitational field magnitude as the ratio of the gravitational force exerted on a test object to the mass of that test object, which is why field strength is measured in N/kg while force is measured in N. The field belongs to whatever created it, and it is the same at that point no matter what you put there.

Why is there no equation for the normal force or for tension?

Because their values are not properties of the objects, they are whatever Newton's laws require in that particular arrangement. A noncontact force can be given a formula because it depends only on the two objects and their separation, so the AP Physics 1 sheet prints the gravitational force in full. A contact force depends on the geometry, on what else is pushing and on how the object is accelerating, none of which a formula can know in advance. So no sheet in any of the four courses prints a line for the normal force or for tension. What the sheet does print is the friction inequality, which caps the friction force at the product of the coefficient and a normal force you had to obtain some other way, and the ideal spring model.

Is air resistance a contact force?

Yes. Air is matter and it touches the object, so drag is in the contact family alongside friction, the normal force and buoyancy. It is worth noting because the word resistance can make it sound like something acting at a distance. In AP Physics 1 you will usually not draw it at all: College Board's appendix lists the modeling assumptions students may make unless a question states otherwise, and two of the five are that air resistance is negligible and that frictional and drag forces are negligible. When a question does put drag in play, it goes in the contact column and it disappears the moment the object is no longer moving through the air.