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Question :
61. As a car goes up a hill, there a : 2102092

61. As a car goes up a hill, there is a force of friction between the road and the tires rolling on the road. The maximum force of friction is equal to:

A. the weight of the car times the coefficient of kinetic friction.

B. the normal force of the road times the coefficient of kinetic friction.

C. the normal force of the road times the coefficient of static friction.

D. zero.

62. As a car moves forward on a level road at constant velocity, the net force acting on the tires is:

A. greater than the normal force times the coefficient of static friction.

B. equal to the normal force times the coefficient of static friction.

C. the normal force times the coefficient of kinetic friction.

D. zero.

63. As a car skids with its wheels locked trying to stop on a road covered with ice and snow, the force of friction between the icy road and the tires will usually be:

A. greater than the normal force of the road times the coefficient of static friction.

B. equal to the normal force of the road times the coefficient of static friction.

C. less than the normal force of the road times the coefficient of static friction.

D. greater than the normal force of the road times the coefficient of kinetic friction.

64. There are six books in a stack, each with a weight of 5.0 N. The coefficient of friction between all the books is 0.20 as is the coefficient between the table and the bottom book. What horizontal push must I just exceed on the next to bottom book to start sliding the top five books off the bottom one?

A. 1.0 N

B. 5.0 N

C. 3.0 N

D. 7.0 N

65. Two objects, A and B, are placed on an inclined plane that can be rotated to different angles of elevation. A starts to slide at twice the angle of elevation that B starts sliding. The respective coefficients for static friction for A and B are m_{A} and m_{B}. Choose the last answer that is correct.

A. m_{B} > m_{A}

B. m_{A} > m_{B}

C. m_{B} = 2 m_{A}

D. m_{A} = 2 m_{B}