Unit 1

Question 1

force that opposes the motion of objects that move through the air

Answer 1

air resistance

Question 2

the maximum speed an object will reach when falling through a substance, such as air

Answer 2

terminal velocity

Question 3

describes the fall of an object on which only the force of gravity is acting

Answer 3

free fall

Question 4

a force that is directed toward the center of a curved or circular path

Answer 4

centripetal force

Question 5

states that if no external forces act on a group of objects, their total momentum does not change

Answer 5

law of conservation of momentum

Question 6

a change in an object’s position relative to a reference point

Answer 6

motion

Question 7

distance and direction of an object’s change in position from the starting point

Answer 7

displacement

Question 8

distance an object travels per unit of time

Answer 8

speed

Question 9

the speed and direction of a moving object

Answer 9

velocity

Question 10

property of a moving object that equals its mass times its velocity

Answer 10

momentum

Question 11

rate of change of velocity; can be calculated by dividing the change in the velocity by the times it takes the change to occur

Answer 11

acceleration

Question 12

acceleration of an object toward the center of a curved or circular path

Answer 12

centripetal acceleration

Question 13

a push or pull exerted on an object

Answer 13

force

Question 14

sum of all the forces that are acting on an object

Answer 14

net force

Question 15

force that opposes the motion between two touching surfaces

Answer 15

friction

Question 16

attractive force between two objects that depends on the masses of the objects and the distance between them

Answer 16

gravity

Question 17

a region of space in which every point has a physical quantity, such as a force

Answer 17

field

Question 18

gravitational force exerted on an object

Answer 18

weight

Question 19

states that an object moving at a constant velocity keeps moving t that velocity unless an unbalanced force acts on it

Answer 19

Newton’s first law of motion

Question 20

tendency of an object to resist any change in its motion

Answer 20

inertia

Question 21

states that the acceleration of an object is in the same direction as the net force on the object, and that the acceleration equals the net force divided by its mass

Answer 21

Newton’s second law of motion

Question 22

states that when one object exerts a force on a second object, the second object exerts a force on the first object that is equal in strength and in the opposite direction

Answer 22

Newton’s third law of motion

Question 23

When a falling object reaches terminal velocity, the force of gravity _______________ the force of air resistance.

Answer 23

equals

Question 24

When an object moves in a circular path, the net force is called a ________________.

Answer 24

centripetal force

Question 25

_______________ is the change in velocity divided by the time needed for the change to occur.

Answer 25

Acceleration

Question 26

Any change of distance over time is called _______________.

Answer 26

speed

Question 27

The distance and direction between the final position and the starting position is the _______________.

Answer 27

displacement

Question 28

Acceleration toward the center of a curved or circular path is called _______________.

Answer 28

centripetal acceleration

Question 29

An object traveling in a circular path is accelerating because its _______________.

Answer 29

direction changes

Question 30

Will a thrown ball or a dropped ball hit the ground first when dropped or thrown from the same height?

Answer 30

Both balls hit the ground at the same time.

Question 31

An object's momentum includes its _______________.

Answer 31

velocity and mass

Question 32

The distance between an object and a reference point is the object's _______________.

Answer 32

position

Question 33

What is the equation for momentum?

Answer 33

p = mv

Question 34

_______________ speed is found by dividing total distance traveled by the total time.

Answer 34

Average

Question 35

_______________ speed is the speed of an object at any instant of time.

Answer 35

Instantaneous

Question 36

If an object has a constant velocity, then it has an acceleration of ____________.

Answer 36

zero

Question 37

A change in velocity means a change in _____________________.

Answer 37

speed, direction, or both

Question 38

Which term best describes the forces on an object with a net force of zero?

Answer 38

balanced forces

Question 39

How does the gravitational force change as two objects move farther apart?

Answer 39

It decreases.

Question 40

What is the gravitational force exerted on an object called?

Answer 40

weight

Question 41

What explains why astronauts seem weightless in orbit?

Answer 41

The spacecraft is in free fall.