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REGENTS PHYSICS PROBLEMS WORKSHEET FRICTION B
REGENTS PHYSICS PROBLEMS WORKSHEET FRICTION B
1. If the coefficient of friction is 0.20, what force parallel to a 30° incline is required to pull a 100 N box up the incline with an acceleration of 2.0 m/sec2?
2. An 80 N box rests on an inclined plane 10 m long and 6 m high for which the coefficient of friction is 0.30. What force parallel to the plane is required to move the box with uniform speed up the plane? Down the plane?
3. The coefficient of friction between a block and the surface on which it slides is 0.18 and the surface is inclined at an angle of 15°. If the block weighs 300 N, what force is needed to drag it up the incline at uniform speed? What force is required to let it slide down the plane at uniform speed?
4. A sled and rider together have a mass of 36 kg. Starting from rest the sled coasts down a 30° incline which is 50 m long. The coefficient of friction is 0.125. What speed will the sled have at the foot of the incline?
5. A 50 kg box is placed on an inclined plane making an angle of 30° with the horizontal. If the coefficient of friction is 0.30, what is the resultant force on the box?
6. A 250 kg safe is to be lowered at constant speed down skids 4.0 m long from a truck bed 2.0 m high. If the coefficient of friction is 0.40, a) Will the safe have to be held back or pulled down? b) What force parallel to the plane is needed for motion at constant speed?
7. An inclined plane 12 m high and 20 m long has a block of mass 50 kg resting at its top. The coefficient of friction is 0.30.
a. What speed would the block have at the bottom if the incline were frictionless?
b. What speed will it actually have (allowing for friction)?
c. How fast will the block be going if it fell 12 m straight down?
8. A 20 N block rests on a plane which makes an angle of 20° with the horizontal. The coefficient of friction between the block and plane is 0.15. Compute the force required to cause the block to slide up the plane at constant speed.
9. A block of wood is placed on one end of a board. Then the end of the board is raised until, when the block is given a slight push, it slides down the board with a uniform velocity. Prove that the coefficient of friction is equal to the tangent of the angle the board makes with the horizontal.
| Create Date : 05 กุมภาพันธ์ 2554 |
| Last Update : 5 กุมภาพันธ์ 2554 14:29:19 น. |
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