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Question :
56. A 250-kg crate placed an adjustable inclined plane. If : 2102091

56. A 250-kg crate is placed on an adjustable inclined plane. If the crate slides down the incline with an acceleration of 0.70 m/s^{2} when the incline angle is 25?, then what should the incline angle be for the crate to slide down the plane at constant speed? (*g* = 9.8 m/s^{2})

A. 12?

B. 21?

C. 25?

D. 29?

57. Doug hits a hockey puck, giving it an initial velocity of 6.0 m/s. If the coefficient of kinetic friction between ice and puck is 0.050, how far will the puck slide before stopping?

A. 19 m

B. 25 m

C. 37 m

D. 57 m

58. It is late and Carlos is sliding down a rope from his third floor window to meet his friend Juan. As he slides down the rope faster and faster, he becomes frightened and grabs harder on the rope, increasing the tension in the rope. As soon as the upward tension in the rope becomes equal to his weight:

A. Carlos will stop.

B. Carlos will slow down.

C. Carlos will continue down at a constant velocity.

D. the rope must break.

59. Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another. The cubes are lined up from left to right and a 36-N force is applied to the left side of the left cube causing all three cubes to accelerate to the right. If the cubes are each subject to a frictional force of 6.0 N, what is the magnitude of the force exerted on the middle cube by the left cube in this case?

A. 12 N

B. 24 N

C. 36 N

D. none of the above

60. Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another. The cubes are lined up from left to right and a 36-N force is applied to the left side of the left cube causing all three cubes to accelerate to the right. If the cubes are each subject to a frictional force of 6.0 N, what is the magnitude of the force exerted on the right cube by the middle cube in this case?

A. 12 N

B. 24 N

C. 36 N

D. none of the above