8PS2 Ch2.1 Gravity and Forces

Gravity and magnetism are examples of what?

• friction

• electrical forces

• contact forces

• 1. noncontact forces

What happens to the gravitational force between two objects as they move farther apart?

• it increases

• it decreases

• it remains the same

• it fluctuates

What causes a falling skydiver to slow down after the parachute opens?

• air resistance

• gravity

• inertia

• reference motion

Which type of friction keeps an object at rest?

• sliding

• rolling

• static

• mobile

What is the difference between weight and mass?

• Weight is the amount of matter in an object, and mass is the gravitational force exerted on an object.

• Mass is the amount of matter in an object, and weight is the gravitational force exerted on an object.

• Weight is the amount of matter in an object, and mass is the size of an object.

• Weight is the size of an object, and mass is the amount of matter in an object.

Key Concept What are some contact forces and some noncontact forces?

Read the example - if it is caused by a contact force choose Contact or if it is caused by a noncontact force choose Noncontact

rain falling ​ (a)  

papers scattered by wind ​ (b)  

a baseball sailing into the outfield ​ ​ (c)  

a magnet attracting a nail ​ (d)  

an elevator ascending ​ (e)  

• Contact
• Noncontact

Complete this concept map by choosing terms from the word bank and placing them in the correct spaces.

a

b

c

d

e

f

g

force

gravity

object

unit

mass

effect

newton

Types of Forces

1. A push or a pull is called a(n) ​ (a)   .

2. A(n) ​ (b)   is a push or a pull on an object by another object that is touching it.

3. A force that one object can apply to another object without touching it is a(n) ​ (c)  

4. Gravity, ​ (d)   , and electric forces are examples of noncontact forces.

5. Forces have ​ (e)   and direction.

• force
• contact force
• noncontact force.
• magnetism
• strength

Types of Forces

6. An arrow can be used to show a force; the ​ (a)   shows the strength of the force, and the direction of the arrow shows the ​ (b)   of the force.

7. Forces are measured in units called ​ (c)   .

• length
• direction
• newtons

What is gravity?

1. ​ (a)   is the amount of matter in an object.

2. ​ (b)   is an attractive force that exists between all objects that have mass.

3. Mass is often measured in ​ (c)   .

• Mass
• Gravity
• kilograms