8/11/2019 Centripetal Force HW

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Centripetal force HW

1. A 1.00 103kg car is driven clockwise around a flat circular track of radius 25.0 m.

The speed of the car is a constant 5.00 m s-1

.

What minimum friction force must exist between the tires and the road to prevent the

car from skidding as it rounds the curve?

a. 1.25 105N

b. 9.80 104N

c. 5.00 103N

d. 1.00 103N

2. A point mass moves through a circular arc of length L and radius r in time t. What isthe angular velocity about the centre of the circle?

a. L/rt

b. r/Lt

c. 2/Lt

d. 2r/t

3. A bucket of water is swung in a vertical circle at arms length of 0.70 m. The

minimum number of revolutions per second it must be swung to keep the water from

spilling out of the bucket is

a. 3.74

b. 2.62

c. 1.68

d. 0.60

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8. A child on a roundabout is traveling in a horizontal circle with a constant speed. The

velocity, acceleration and the resultant horizontal force on the child are all vectors.

Which diagram shows

the correct directions for these vectors?

A

B

C

D

9. An aircraft is moving in a horizontal plane at a constant speed. It banks at an angle

of 50oto the vertical in order to make a turn as shown in the diagram below. The only

forces acting on the aircraft are lift, L and weight, W.

What is the ratio of the centripetal force to the weight of the aircraft?

a. 0.643

b. 0.766

c. 0.839

d. 1.19

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10. A toy car, of mass 0.10 kg, is travelling along a track which contains a vertical

circular loop of radius 0.10 m as shown in the diagram.

What is the minimum entry speed v of the car required to prevent it from falling off the

track at the top of the loop?

a. 0.3 m s-1

b.

1.0 m s-1

c. 1.4 m s

-1

d. 2.2 m s-1