- Submitted By: tieulong
- Date Submitted: 10/26/2010 7:05 PM
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7.3 Circular Motion pages 163–168

14. Consider the following changes to the example problem (pp. 165-166).

a. The mass is doubled, but all other quantities remain the same. What would be the effect on the velocity, acceleration, and force?

Since rand T remain the same, [pic]

remain the same. The new value of the mass is m2 = 2m1. The new force is F2 = m2 a= 2m1 a= 2 F1, double the original force.

b. The radius is doubled, but all other quantities remain the same. What would be the effect on the velocity, acceleration, and force?

[pic]

[pic] c. The period of revolution is half as large, but all other quantities remain the same. What would be the effect on the velocity, acceleration, and force?

[pic]

15. A runner moving at a speed of 8.8 m/s rounds a bend with a radius of 25 m.

a. What is the centripetal acceleration of the runner?

b. What agent exerts the force on the runner?

R/ a.

[pic]

b.

16. Racing on a flat track, a car going 32 m/s rounds a curve 56 m in radius.

a. What is the car’s centripetal acceleration?

b. What minimum coefficient of static friction between the tires and road would be needed for the car to round the curve without slipping?

R/ a.

[pic]

b.

[pic]

49. A 615-kg racing car completes one lap in 14.3 s around a circular track with a radius of 50.0 m. The car moves at constant speed.

a. What is the acceleration of the car?

b. What force must the track exert on the tires to produce this acceleration?

R/a.

[pic]

b.

[pic]

50. An athlete whirls a 7.00-kg hammer tied to the end of a 1.3-m chain in a horizontal circle. The hammer makes one revolution in 1.0 s.

a. What is the centripetal acceleration of the hammer?

b. What is the tension in the chain?

R/a.

[pic]

b.

[pic]

51. A coin is placed on a vinyl stereo record making 33 1/3 revolutions per minute.

a. In what direction is the acceleration of the coin?

b. Find the magnitude of the acceleration when the coin is placed 5.0, 10, and 15 cm from...