Name:______date:______period:______(2)

Science 8: Ch 13.1 Gravity: A Force of Attraction (pages 370-375)

Key Concept
Gravity is a ______of attraction between objects that is due to their ______
Why is leaping on the moon easier than leaping on Earth?
Define gravity
How can the force of gravity change the motion of an object?
Why is all matter affected by gravity?
In which direction does gravitational force bring objects?
Why don’t we see your book moving toward you on it’s own?
Where does the gravitation force of Earth pull all matter?
What must you apply to overcome Earth’s gravitational force to lift an object?
Based on watching an apple fall from an apple tree, what did Newton determines caused the apple to fall?
Did Newton apply this same idea to the reason why the moon moves circularly around the Earth?
What does the law of universal gravitation describe?
Why is the law mentioned above called a law?
What does the law of universal gravitation state?
The magnitude of the force attracting all objects to each other depends on what two things? / 1.
2.
When does the gravity between two objects increase?
Why is a cat easier to pick up than an elephant?
Is there also gravity between the cat and the elephant?
Which has a stronger gravitational force, the cat and the elephant or the elephant and Earth?
It’s easier for astronaut’s to bounce on the moon than on the Earth. Is the reason because the astronauts are not being pulled down with as much force because the moon has less mass?
Why doesn’t the gravitational force of the sun pull you towards the sun?
The force of gravity changes as what changes?

Looking at Figure 5, show how distance affects gravitational force. Remember length of arrows determines magnitude.

How does gravity play an important role in maintain the shape of the solar system?
Define weight.
What us the SI unit for weight?
What does the term weight usually refer to?
Is weight and mass the same thing?
Which can change is relation to gravitational force, mass or weight?
How is mass usually expressed (units)?
Looking at Figure 6 on page 374, how much less does an astronaut weigh on the moon?
Does gravity act on static objects?
What is gravity balanced by?
The gravity pushing down on a picture frame on a wall is balanced by what?
The gravity pushing down on a picture frame on a shelf is balanced by what?
In the last two questions, both pictures remain static, meaning what?