A 2.00-kg block is at rest on a horizontal plank that is 1.50 m long. When one end of the plane is raised to 0.50 m, the block starts sliding down. What is the coefficient of static/starting friction between the block and the plank? O 0.43 O 0.35 0.33 O 0.53

Determine the minimum value of weight W which may be applied without causing the 50-lb block to slip. The coefficient of static friction between the block and the plane is µ; = 0.2, and between the rope and the drum D µ3 = 0.3. W 45°

A 500 N block is being pushed along a frictionless horizontal surface by a force of 150 N at 40° to the horizontal. What is the normal force from the surface on the object? A) 96 N B) 150 N C) 404 N D) 500 N E) 596 N 150 N 500 N 40.0°

A 20-kg box of oranges slides from rest down a frictionless incline from a height of 5.0 m. A constant frictional force, introduced at point A, brings the block to rest at point B, 19 m to the right of point A. What is the coefficient of kinetic friction, Hk, of the surface from A to B? 5.0 m A 19 m 0.11 0.52 0.26 0.33 0.47

A ski that is placed on snow will stick to the snow. However, when the ski is moved along the snow, the rubbing warms and partially melts the snow, reducing the coefficient of friction and promoting sliding. Waxing the ski makes it water repellent and reduces friction with the resulting layer of water. A magazine reports that a new type of plastic ski is especially water repellent and that, on a gentle 230 m slope in the Alps, a skier reduced his top-to-bottom time from 69 s with standard skis to 42 s with the new skis. Old skis acceleration = 0.097 m/s2 New skis acceleration = 0.26 m/s2 Assuming a 3.0° slope, compute the coefficient of kinetic friction for each case. Old skis _______ New skis  _______

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If the coefficient of static friction between all surfaces in contact is µg = 0.3 and a determine force P that must be applied to wedge A in order to lift the block weighing 500 N. The weight of wedge A is negligible compared to the block. B P

10) A push of magnitude P acts on a box of weight W as shown in the figure. The push is directed at an angle 0 below the horizontal, and the box remains a rest. The box rests on a horizontal surface that has some friction with the box. What is the friction force on the box due to the floor? P. W

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