physics vocab

models

a pattern, plan, representation designed to show the structure of an object, system or concept

hypothesis

reasonable explanation for observations that can be tested

controlled experiment

an experiment that tests only one factor at a time using a comparison of a control group with an experimental group

accuracy

description on how close a measurement is to the correct value of the quantity measured

system

a set of particles or interacting components considered to be a distinct physical entity for the purpose of study

precision

degree of exactness of a measurement

significant figures

digits in a measurement that are known with certainty

frame of reference

a system for specifying the precise location of objects in space and time

displacement

the change in position of an object

average velocity

total displacement divided by the time interval during which the displacement occurred

instantaneous velocity

velocity of an object at some instant or at a specific point in the object's path

acceleration

rate at which velocity changes over time

free fall

the motion of a body when only the force due to gravity is acting on the body

scalar

a physical quantity that has magnitude but no direction

vector

a physical quantity that has both magnitude and direction

resultant

a vector that represents the sum of two or more vectors

components

the projections of a vector along the axes of a coordinate system

projectile motion

the curved path that an object follows when thrown or projected near the surface of earth

force

an action on an object which may change the objects state of rest or motion

contact force

forces that involve physical contact

field force

does not involve physical contact between two objects

inertia

tendency of an object to resist being moved

net force

single force whose external effects on a body are the same as the effects of several forces acting on that body

equilibrium

state in which the net force on an object is zero

weight

measure of the gravitational force exerted on an object

normal force

force that acts on a surface in a direction perpendicular to the surface

static friction

force that resists the initiation of sliding motion between two surfaces that are in contact and at rest

kinetic friction

force that opposes the movement of two surfaces that are in contact and are sliding over each other

coefficient of friction

ratio of magnitude of the force of friction between two objects in contact to the magnitude of the normal force with which the objects press against each other

work

amount of energy transferred by a force acting through a distance.

kinetic energy

energy of an object that is due to the objects motion

work kinetic energy theorem

net work done by all the forces acting on an object is equal to the change in the objects kinetic energy

potential energy

energy associated with an object because of the position, shape or condition of the object

gravitational potential energy

the potential energy storied in the gravitational fields of interacting bodies

elastic potential energy

energy available for use when a deformed elastic object returns to its original configuration

spring constant

a parameter that is a measure of a springs resistance to being compressed or stretched

mechanical energy

sum of kinetic energy and all forms of potential energy

power

a quantity that measures the rate at which work is done or energy is transformed

momentum

a quantity defined as the product of the mass and velocity of an object

impulse

product of the force and the time over which the force acts on an object

perfectly inelastic collision

a collision in which two objects stick together after coinciding

elastic collision

a collision in which the total momentum and the total kinetic energy are conserved

centripetal acceleration

the acceleration directed toward the center of a circular path

gravitational force

mutual force of attraction between particles of matter

torque

quantity that measures the ability of a force to rotate an object around some axis

lever arm

perpendicular distance from the axis of rotation to a line drawn along the direction of the force

Newtons law of gravity

all masses are attached to one another.

period

time required for one cycle to pass a given point.