TCI Forces and Energy: Gravity

GRAVITY!

(Please log in and open book to pg. 64)

Reading - Sections 3-6 ​

Multiple Choice

Gravity is a ________ force.

• Pushing

• Pulling

Multiple Choice

Gravity pulls all objects __________.

• Down

• Up

• Toward the center of the object

• Toward outer space

Multiple Choice

Which combination of objects would experience the largest gravitational force?

• A cat and a couch

• A planet and a star

• A human and a planet

Open Ended

What two variables affect the strength gravitational force?

Section 3 (page 64-65)

The Strengths of Graviational Forces

Key Point:

The gravitational force between two objects depends on two factors: the masses of the objects and the distance between them. The strength of the gravitational forces between two objects is greater when one or both objects has a large mass.

Open Ended

What kind of evidence did Sir Isaac Newton find that demonstrated the effects of gravity?

Open Ended

Why is it that you might feel the effect of gravitational forces between you and Earth, but not between you and a classmate?

Section 4 (page 67)

Gravitational Fields

Key Points:

A model called a force field will describe what the force on an object would be if the object were placed in any location in space.

The strength of a gravitational field decreases with distance.

Multiple Choice

What is true about gravitational fields?

• Earth's gravitational field is weak near Earth's surface.

• The strength of a gravitational field increases with distance.

• The moon has no gravitational field

• The strength of a gravitational field decreases with distance.

Draw

Draw the graviational field around Earth.

Open Ended

How is the strength of the gravitational field represented in a gravitational field diagram?

Multiple Choice

How would you expect the arrows in the gravitational field lines to appear close to Earth?

• Lines would be close together

• Lines would be further apart

• Lines would not exist

• Lines would be going in opposite directions

Section 5 (page 68)

Mass and Weight

Key Points:

Weight is the amount of gravitational force on an object. It is measured in newtons (N), just like other forces. An object’s weight depends on its mass. Mass is the amount of matter in an object. Mass is measured in kilograms (kg).

However, an object’s weight can change without changing mass if the gravitational force on it changes.

Draw

Draw the difference between mass and weight.

Multiple Choice

What unit is usually used to measure mass?

• Pound (lbs)

• Meter (m)

• Kilogram (kg)

• Newton (N)

Multiple Choice

What scientific unit is usually used to measure weight?

• Pound (lbs)

• Meter (m)

• Kilogram (kg)

• Newton (N)

Open Ended

How can an object’s weight change without changing mass?

Section 6 (page 69)

Weight in Orbit

Key Points:

Gravity causes the space station to orbit Earth. As the space station “falls around” Earth, everything inside it, including the astronauts, fall with it.

Open Ended

What conditions must be met for an object in motion to be "weightless"?

Multiple Choice

How does the speed of the space station and the astronauts in the space station compare?

• Space station is faster

• Astronauts are faster

• Neither one is moving

• Both are the same speed