test 1 physics

1-4

Acceleration

The rate at which velocity changes with time; the change in velocity may be in magnitude or direction or both, usually measured in m/s squared.

Air resistance

The force of friction acting on an object due to its motion in air.

speed

The distance traveled per time.

vector

A quantity whose description requires both magnitude and direction.

Velocity

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The speed of an object and specification of its direction of motion

volume

The quantity of space an object occupies.

weight

The force due to gravity on an object. More specifically, the force with which a body presses against a supporting surface.

Equilibrium rule

The vector sum of forces acting on a non accelerating object equals zero: (sideways M)F = 0.

force

Simply stated, a push or a pull.

free fall

Falling only under the influence of gravity--falling without air resistance

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friction

The resistive force that opposes the motion or attempted motion of an object past another with which it is in contact, or through a fluid.

inertia

The property of things to resist changes in motion.

mass

The quantity of matter in an object. More specifically, the measure of the inertia or sluggishness that an object exhibits in response to any effort made to start it, stop it, deflect it, or change in any way its state of motion.

net force

The combination of all forces that act on an object.

support force

The force that supports an object against gravity, often called the normal force.

Newton's first law of motion

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Every object continues in a state of rest, or in a state of motion in a straight line at constant speed, unless acted on by a net force

Newton's second law of motion

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The acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object

Newton's third law of motion

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object

terminal velocity

Terminal speed in a given direction (often downward)

**Students**

Static Equilibrium

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Objects at rest with a net force of 0.

dynamic Equilibrium

Objects moving at a constant velocity with a net force of 0.

scalar quantity

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can be described by magnitude only and has no direction \n example: distance, speed, mass

vector quantity

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a quantity that has both magnitude and direction \n example: displacement, velocity, force

Momentum

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A quantity defined as the product of the mass and velocity of an object.

impulse

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the product of the force acting on an object and the time during which it acts

Conservation of momentum

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In the absence of an outside force, the total momentum will be conserved.

mv(before )= mv(after event)

elastic collision

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A collision in which colliding objects rebound without lasting deformation or the generation of heat.

inelastic collision

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A collision in which the colliding objects become distorted, generate heat, and possibly stick together

work

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A result of a force moving an object a certain distance. \n W = Fd

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the property of a system that enables it to do work

potential energy

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Stored Energy

kinetic energy

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Energy of motion \n KE = 1/2mv^2

power

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the time rate of work \n Power = work done/time interval

Law of universal gravitation

Every body in the universe attracts every other body with a force the strength of which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers: F = G m1m2 d 2

Inverse Square Law

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The intensity of an effect from a localized source spreads uniformly throughout the surrounding space and weakens with the inverse square of the distance

Weight

The force that an object exerts on a supporting surface (or, if suspended, on a supporting string), which is often, but not always, due to the force of gravity.

Weightless

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Being without a support force, as in free fall.

Projectile

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any object that moves through the air or through space under the influence of gravity.