 # Science--Chapter 2B

Chapter 2B

Force and Motion

1. How do forces affect motion?

A force is a push or pull that can make an object move.

Gravity is the force that pulls two objects together and pulls you toward the center of the earth.

Friction slows down or stops objects that are in motion.

2. How does energy affect motion?

Potential energy is energy that an object has because of position.
Kinetic energy is the energy an object has because of its motion.
Mechanical, electrical, and chemical energy are forms of energy that can affect motion.

3. How are work and motion related?

When a force moves an object, work is done.

Simple machines are tools with one or two parts that are used to make work easier.

Compound machines are made up of two or more simple machines; complex machines aer made of many simple and compound machines.

Vocabulary

Force                           a push or a pull on an object that can cause it to change motion

Gravity                         a force that pulls any two objects toward one another, such as you toward the center of the earth

Inertia                           the tendency of a moving object to stay in motion or a resting object to stay at rest

Friction             a force that slows the motion of moving objects

Energy                          the ability to do work

Potential energy            energy that an object has because of position

Kinetic energy              energy of motion

Mechanical energy        the kind of energy an object has because it can move or because it is moving

Chemical energy           energy that comes from chemical changes

Electrical energy           energy that comes from the flow of electricity

Work                           the result of a force moving an object

Simple machine a machine made of one or two parts

Compound machine      a machine made of two or more simple machines

Complex machine         a machine made of many simple and compound machines