# 8th Grade Physical Science 2nd Semester Final Exam Review

Newton
the scientist who gave us the Laws of Motion

3
Laws of Motion

Second Law
that force is equal to mass times acceleration (F=MA)

First Law
law explains why we need to wear seat belts

Third Law
law says that for every action there is an equal and opposite reaction

Second Law
law says that heavier objects require more force than lighter objects to move or accelerate them

Third Law
law explains how rockets are launched into space

Work
is done when a force causes an object to move in the same direction that the force is applied

Joules
Work is measured in

Watts
Power is measured in

Power
is how quickly work is done

Simple Machine
is a machine that does work with only one movement

Compound Machine
is a machine made up of a combination of simple machines

Pulley
consists of grooved wheel with a rope or cable wrapped over it

Wheel and Axle
consist of two circular objects of different sizes that are attached in such a way that they rotate together

Frequency
number of wavelengths that pass any point per second is

Compression
is a part of a wave where the particles are close together

Acceleration
measured in m/s^2

Crest
the highest wave peak of a wave is the

Deceleration
The slowing down of objects is known as

Trough
the lowest point on a wave

simple machine
A tool that makes work easier

force
push or pull

Incline Plane
is a flat surface that is higher on one end

energy
the ability to do work

acceleration
the rate at which speed changes

average speed
the distance an object travels over time