Lesson 2 : Gravity and Friciton

Question 1

What is gravity?

Answer 1

a force of attraction between objects due to their masses

Question 2

What is mass?

Answer 2

the amount of matter in an object

Question 3

What is weight?

Answer 3

the measure of the pull of gravity on an object

Question 4

Mass is _____________, while weight can ___________.

Answer 4

constant, change

Question 5

What is mass measured in?

Answer 5

grams or kilograms

Question 6

What is weight measured in?

Answer 6

newtons

Question 7

Every object exerts a _____________________ pull on another object.

Answer 7

gravitational

Question 8

Why do tides occur?

Answer 8

the gravity between the moon and Earth

Question 9

What happens if the mass of a massive object decreases?

Answer 9

the gravitational force decreases

Question 10

What happens if the mass of a massive object increases?

Answer 10

the gravitational force increases

Question 11

What happens if the distance between two massive objects increases?

Answer 11

the gravitational force decreases

Question 12

What happens if the distance between two massive objects decreases?

Answer 12

the gravitational force increases

Question 13

What is friction?

Answer 13

a contact force that resists motion between two objects

Question 14

If the surface is smooth,

Answer 14

there will be less friction

Question 15

If the surface is rough,

Answer 15

there will be more friction

Question 16

How do you reduce friction?

Answer 16

by adding a lubricant or by replacing the sliding friction by rolling friction

Question 17

How do you increase friction?

Answer 17

increasing the weight of the object

Question 18

What is air resistance?

Answer 18

a force that opposes the motion of objects through the air

Question 19

What is air resistance in other words?

Answer 19

friction between a moving object and the air around the object

Question 20

What factors affect air resistance?

Answer 20

size, shape, speed, and density