Unit 5: Uniform Circular Motion Flashcards

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0
Q

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

the object is accelerating

A

true

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1
Q

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

all of the forces acting on it are balanced

A

false

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2
Q

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

its speed is changing

A

false

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3
Q

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

its velocity is constant

A

false

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4
Q

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

its centripetal force is perpendicular to its centripetal acceleration

A

false

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5
Q

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

it must have only one force acting on it

A

false

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6
Q

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

A

false

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7
Q

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

the period is constant

A

true

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8
Q

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

A

false

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9
Q

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

the velocity is in the same direction as the acceleration

A

false

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10
Q

True or False:

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

A

true

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11
Q

True or False:

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

A

false

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12
Q

True or False:

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

A

false

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13
Q

True or False:

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

A

false

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14
Q

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

A

false

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15
Q

True or False:

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

A

true

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16
Q

True or False:

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

A

true

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17
Q

True or False:

all objects in circular motion must be accelerating

A

true

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18
Q

True or False:

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

A

false

19
Q

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

A

true

20
Q

True or False:

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

A

false

21
Q

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

A

false

22
Q

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

A

false

23
Q

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

all of the forces acting on it are balanced

A

false

24
Q

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

the object’s velocity is constant

A

false

25
Q

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

the object’s centripetal force is changing

A

true

26
Q

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

the object’s centripetal acceleration is constant

A

false

27
Q

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

the object’s speed is changing

A

false

28
Q

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

the magnitude of the centripetal force is changing

A

false

29
Q

The centripetal force and the velocity are

a) in the same direction
b) perpendicular
c) in opposite directions
d) none of these

A

b) perpendicular

30
Q

The centripetal force and the centripetal acceleration are

a) in the same direction
b) perpendicular
c) in opposite directions
d) none of these

A

a) in the same direction

31
Q

The velocity and centripetal acceleration are

a) in the same direction
b) perpendicular
c) in opposite directions
d) none of these

A

b) perpendicular

32
Q

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

A

d) none of these

33
Q

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

A

a) 0.1 seconds

34
Q

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

A

b) decreases

35
Q

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

A

a) quadruple

36
Q

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

A

a) 9

37
Q

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

A

e) none of these

38
Q

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

A

c) only 1 circle

39
Q

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

A

b) Bug 2

40
Q

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

A

c) neither

41
Q

Which of the following are constant for an object in circular motion?

a) velocity
b) acceleration
c) centripetal force
d) none of these

A

d) none of these

42
Q

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

A

b) velocity

43
Q

For an object in circular motion, all forces on the object

a) never balance
b) always balance
c) sometimes balance

A

a) never balance

44
Q

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

A

d) not enough information

45
Q

True or false: centripetal force is a vector

A

true