Principles of Force and Motion

Everything to know about force and motion for the PSSA's!!

May the FORCE be with you! Learn about Force and Motion!!!

You are always in motion and so is the world around you. Scientists study different types of motion all around the world.

Check out the video below for an example of how forces can change the motion of an object.


Vocabulary Words you should know


Motion is a change in position.


The position of an object is its location.


A force is a push or a pull.


Friction is a force that acts between two surfaces that rub against each other.


Gravity is the force of attraction between two objects.

Balanced Forces

Balanced Forces do not change the motion of an object.

Unbalanced Forces

Unbalanced Forces change the motion of an object.


Question 1.

Which of these always happens when a ball is in motion?
A. Moves north
B. Changes direction
C. Moves faster
D. Changes Position

Question 2.

True or False?
An object in motion stops when a force is not applied.

Question 3.

A child throws a ball up and it comes down. Does it matter how high you throw a ball for it to come down?

Question 4.

If Earth had a very small mass, would gravity be stronger or weaker?