A force exerted by a surface on an object. Its direction is parallel to the surface, and the force is in the direction that opposes motion.

Back

Newton's 3rd Law

Front

Forces occur in pairs. The forces are equal in magnitude and opposite in direction. The forces act on different objects.

Back

Newton's Law of Gravitation

Front

The weight force between 2 objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Back

normal force

Front

The force exerted by a surface on an object pressing against the surface. The normal force is in a direction perpendicular to the surface.

Back

elastic collision.

Front

A collision in which the colliding objects bounce off of each other. Momentum is conserved. Kinetic energy is conserved if the collision is perfectly elastic.

Back

momentum (p)

Front

The product of an object's mass and its velocity. p = mv. It can be positive or negative.

Back

thermal energy (Eth)

Front

The energy associated with the microscopic kinetic energy of the atoms that make up an object. The atoms in warmer objects vibrate at faster speeds.

Back

force (F)

Front

A push or a pull. Measured in newtons.

Back

Newton's 2nd Law

Front

a = ∑F ÷ m. Acceleration is directly proportional to net force and inversely proportional to mass.

Back

kinetic energy (K)

Front

The energy of motion. K = 1/2 • m • v^2

Back

weight

Front

A long-range force caused by the gravitational pull of the Earth (or other object) on an object.

Back

uniform circular motion

Front

Motion in a circle at constant speed. The velocity (the direction) is constantly changing and the direction of this change (the acceleration) is toward the center of the circle.

Back

spring energy (Us)

Front

The stored energy of an object due to compression or stretching. Us = 1/2 • k • ∆x^2 ( k = spring constant)

Back

displacement (∆x)

Front

The change in position of an object. Can be positive or negative.

Back

inelastic collision

Front

A collision in which the colliding objects stick together. Momentum is conserved but kinetic energy is not.

Back

conservation of energy

Front

Energy is conserved in an isolated system (initial energy = final energy). Energy can change forms.

Back

velocity (v)

Front

The rate at which an object changes its position. Can be + or -. Equal to the slope on a position vs time graph.

Back

impulse (J)

Front

The product of average force and time, also equal to the area under a F vs t curve. (J = Favg • ∆t)

Back

gravitational potential energy (Ug)

Front

The stored energy of an object due to its height. Ug = mgh

Back

work (W)

Front

Energy transfer into or out of a system due to the application of force. Work is equal to force times distance. (W = F • d)

Back

net force (∑F)

Front

The sum of all forces on an object. If ∑F = 0, then a = 0. If a = 0, then ∑F = 0. (a = ∑F ÷ m)

Back

distance

Front

The length of the path travelled by an object. Always positive.

Back

acceleration of an object in freefall (g)

Front

Near Earth's surface, free-falling objects accelerate at a rate of approximately 10 meters/second per second.

Back

speed (v)

Front

speed = distance travelled in a given time interval ÷ time interval. Always positive.

Back

impulse - momentum theorem

Front

An impulse causes a change in momentum that is equal to the impulse. (J = ∆p)

Back

mass (m)

Front

The amount of matter in an object.

Back

spring force

Front

A contact force. If an object is compressed or stretched, it can exert a force in the opposite direction.

Back

acceleration (a)

Front

The rate at which velocity changes. a = ∆v ÷ ∆t. It equals the slope on a velocity vs time graph.

Back

conservation of momentum

Front

Momentum is conserved (initial momentum = final momentum) in an isolated system.

Back

position (x)

Front

An object's location at a particular instant in time.