1. Chapter 5 Matter In Motion
Section 4 – Gravity: A Force of Attraction pp

2. IMPORTANT DEFINITIONS
Gravity – a force of attraction between objects that is due to their masses.
Weight – a measure of the gravitational force exerted on an object
Mass – the amount of matter in an object.

3. MASS AND WEIGHT
Mass and Weight ARE NOT the same thing!
WEIGHT
MASS

4. MASS VS. WEIGHT Mass: Expressed in grams or kilograms
Does not change no matter where you are
Measured using a triple beam balance or an electronic balance
Amount of matter in an object

5. MASS VS. WEIGHT Weight Expressed in Newtons
Measure of gravitational force on an object
6 times less on the moon than on Earth
Changes when gravitational force changes
Measured by using a Spring scale

6. NEWTON’S LAW OF UNIVERSAL GRAVITATION
All objects in the universe attract each other through gravitational force. The size of the force depends on:
The masses of the objects
The distance between the objects

7. NEWTON’S LAW OF UNIVERSAL GRAVITATION
Gravitational force
increases as
mass increases.
Gravitational force decreases as mass decreases.

8. NEWTON’S LAW OF UNIVERSAL GRAVITATION
Gravitational force decreases as distance between two objects increases.
Gravitational force increases as distance between two objects decreases.