A wooden sled supporting a large stone is pulled up the track inclined at 15ᵒ with the horizontal. The combined mass between the sled and the stone is 750 kg and the coefficient of friction between the sled runner and the track is are μs = 0.40 and μk = 0.30. Determine the force P required to: a. start the sled up the track b. keep the sled from moving after it has been started c. to prevent the sled from sliding down.

A wooden sled supporting a large stone is pulled up the track inclined at 15ᵒ with the horizontal. The combined mass between the sled and the stone is 750 kg and the coefficient of friction between the sled runner and the track is are μs = 0.40 and μk = 0.30. Determine the force P required to: a. start the sled up the track b. keep the sled from moving after it has been started c. to prevent the sled from sliding down.

International Edition---engineering Mechanics: Statics, 4th Edition

4th Edition

ISBN:9781305501607

Author:Andrew Pytel And Jaan Kiusalaas

Publisher:Andrew Pytel And Jaan Kiusalaas

Chapter7: Dry Friction

Section: Chapter Questions

Problem 7.3P: Two identical chairs, each weighing 14 lb, are stacked as shown. The center of gravity of each chair...

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Two identical chairs, each weighing 14 lb, are stacked as shown. The center of gravity of each chair is denoted by G. The coefficient of static friction is 0.2 at B (the contact point between the chairs) and 0.35 at A, C, and D. Determine the smallest force P that would cause sliding.
The square-threaded screw 0f the C-clamp has a mean diameter of 8 mm and a pitch of 1.6 mm. The coefficient of static friction between the threads is 0.2. If the torque C=1.50Nm is used to tighten the clamp, determine (a) the clamping force; and (b) the torque required to loosen the clamp.
The panel of weight W with its center of gravity at G is placed between vertical guides and released. Determine the largest height h for which the panel will not slide down due to binding at corners A and B. The coefficient of static friction between the panel and the guides is 0.5.
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The brake pads at C and D are pressed against the cylinder by the spring BF. The coefficient of static friction between each pad and the cylinder is 0.15. Find the smallest tension in the spring that would prevent the cylinder from rotating when the clockwise couple M=2200lbin. is applied. Neglect the weights of the members.
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