Unit 5: Uniform Circular Motion

Question 0

True or False: If an object is in uniform circular motion…

the object is accelerating

Answer 0

true

Question 1

True or False: If an object is in uniform circular motion…

all of the forces acting on it are balanced

Answer 1

false

Question 2

True or False: If an object is in uniform circular motion…

its speed is changing

Answer 2

false

Question 3

True or False: If an object is in uniform circular motion…

its velocity is constant

Answer 3

false

Question 4

True or False: If an object is in uniform circular motion…

its centripetal force is perpendicular to its centripetal acceleration

Answer 4

false

Question 5

True or False: If an object is in uniform circular motion…

it must have only one force acting on it

Answer 5

false

Question 6

True or False: If an object is in uniform circular motion…

the mass of the object dies not affect how much centripetal force is needed

Answer 6

false

Question 7

True or False: If an object is in uniform circular motion…

the period is constant

Answer 7

true

Question 8

True or False: If an object is in uniform circular motion…

if the centripetal force that kept it in the circle is removed, a force tangent to the circle will act on the object

Answer 8

false

Question 9

True or False: If an object is in uniform circular motion…

the velocity is in the same direction as the acceleration

Answer 9

false

Question 10

True or False:

when a yo-yo is spun overhead in a horizontal circle, the tension in the string supplies the centripetal force

Answer 10

true

Question 11

True or False:

when a car is going around a circular turn, friction opposes the centripetal force

Answer 11

false

Question 12

True or False:

an object moving in a circle can have a net force of zero

Answer 12

false

Question 13

True or False:

for a satellite in orbit around the earth, the centripetal force is supplied by the satellite’s high velocity

Answer 13

false

Question 14

True or False:

if you were spinning in the rotor ride and the ride suddenly disappeared, you would have a force exerted on you in a direction tangent to the circle

Answer 14

false

Question 15

True or False:

every object that moves in a circle must have a net force acting on it

Answer 15

true

Question 16

True or False:

objects in circular motion must have velocities that are perpendicular to the centripetal force at any given instant

Answer 16

true

Question 17

True or False:

all objects in circular motion must be accelerating

Answer 17

true

Question 18

True or False:

for an object moving in a circle, the magnitude of the centripetal force is constantly changing

Answer 18

false

Question 19

True or False:

for an object moving in a circle, the centripetal force and centripetal acceleration must both point in the same direction at any given point in time

Answer 19

true

Question 20

True or False:

when clothes spin in a washer, a force pushed them toward the drum (outward from the center)

Answer 20

false

Question 21

True or False:

when a car is making a circular turn, the force pushing the car toward the center of the circle is balanced by friction force

Answer 21

false

Question 22

True or False:

when you swing a yo-yo in a circle on the floor, the velocity of the yo-yo provides the centripetal force

Answer 22

false

Question 23

True or False: If an object is in uniform circular motion…

all of the forces acting on it are balanced

Answer 23

false

Question 24

True or False: If an object is in uniform circular motion... the object's velocity is constant

Answer 24

false

Question 25

True or False: If an object is in uniform circular motion... the object's centripetal force is changing

Answer 25

true

Question 26

True or False: If an object is in uniform circular motion... the object's centripetal acceleration is constant

Answer 26

false

Question 27

True or False: If an object is in uniform circular motion... the object's speed is changing

Answer 27

false

Question 28

True or False: If an object is in uniform circular motion... the magnitude of the centripetal force is changing

Answer 28

false

Question 29

The centripetal force and the velocity are a) in the same direction b) perpendicular c) in opposite directions d) none of these

Answer 29

b) perpendicular

Question 30

The centripetal force and the centripetal acceleration are a) in the same direction b) perpendicular c) in opposite directions d) none of these

Answer 30

a) in the same direction

Question 31

The velocity and centripetal acceleration are a) in the same direction b) perpendicular c) in opposite directions d) none of these

Answer 31

b) perpendicular

Question 32

During one period, an object in uniform circular motion travels a distance equal to a) 3.14 b) 3.14(r)^2 c) 2(3.14) d) none of these

Answer 32

d) none of these

Question 33

A can on the end of a string swings through 10 revolutions per second. Its period is a) 0.1 seconds b) 10 seconds c) 0.01 seconds d) 100 seconds

Answer 33

a) 0.1 seconds

Question 34

A bug stands on a record spinning at 45 rev/min. As the bug walks toward the center of the record, it's tangential velocity a) increases b) decreases c) stays the same

Answer 34

b) decreases

Question 35

An object is in uniform circular motion. If the mass is quadrupled while the speed and radius remain unchanged, the centripetal force required will a) quadruple c) be 16x the original b) double d) be half the original

Answer 35

a) quadruple

Question 36

An object is in uniform circular motion. If the mass and radius are held constant but the speed is multiplied by 3, the centripetal force required will be __ times the original force a) 9 c) 3 b) 1/9 d) 1/3

Answer 36

a) 9

Question 37

A ball on the end of a string 2m long swings through 24 circles every 4s. The period for this motion is a) 6 seconds b) 3 seconds c) 12 seconds d) 4 seconds e) none of these

Answer 37

e) none of these

Question 38

During one period, an object in circular motion can move through a) less than 1 circle b) more than 1 circle c) only 1 circle d) a number of circles that varies

Answer 38

c) only 1 circle

Question 39

Bug 1 and Bug 2 both stay 15 cm from the center of the rotating CD they have landed on. Bug 2 has twice the mass of Bug 1. Which Bug has the largest centripetal force as they traveled around with the CD? a) Bug 1 b) Bug 2 c) neither

Answer 39

b) Bug 2

Question 40

Bug 1 and Bug 2 both stay 15 cm from the center of the rotating CD they have landed on. Bug 2 has twice the mass of Bug 1. Which Bug has the largest centripetal acceleration as they traveled around with the CD? a) Bug 1 b) Bug 2 c) neither

Answer 40

c) neither

Question 41

Which of the following are constant for an object in circular motion? a) velocity b) acceleration c) centripetal force d) none of these

Answer 41

d) none of these

Question 42

A rotor ride is spinning at the normal rate. For fun, the operator of the ride doubles the rotation rate. Which of the following must also double as a result of the operator's action? a) centripetal acceleration b) velocity c) centripetal force d) none of these

Answer 42

b) velocity

Question 43

For an object in circular motion, all forces on the object a) never balance b) always balance c) sometimes balance

Answer 43

a) never balance

Question 44

Car 1 and Car 2 have the same mass and identical tires. Both cars are making circular turns on identical surfaces. The radius of Car 2's turn is twice the radius of Car 1's turn. Which of the following is the same for both cars? a) centripetal acceleration b) centripetal force c) period d) not enough information

Answer 44

d) not enough information

Question 45

True or false: centripetal force is a vector

Answer 45

true