Mechcrack - Engineering eclass: Friction Worksheet

1.Two blocks A and B of weight 500 N and 750 N respectively are connected by a cord that passes over a frictionless pulley as shown in figure. µ between the block A and inclined plane is 0.4 and the between the block B and the inclined plane is 0.3. Determine the force P to be applied to block B to produce the impending motion of block B down the plane.

2. Determine the maximum value of P that can be applied to the roller shown in figure without causing it to rotate. Coefficient of friction for all contact surfaces is 0.5.

3. Two 6^owedges are used to push the block horizontally as shown. Calculate the minimum force P required to push the block of weight 10000 N. µ = 0.25 for all surfaces.

4. A block weighing 1000 N is raised against a surface inclined at 60^o to the horizontal by means of a 15^owedge as shown in figure. Find the horizontal force P which will just start the block to move if the coefficient of friction between all the surfaces of contact be 0.2. Assume the wedge to be of negligible weight.

5. Wedge A supports a load of W = 5000 N which is to be raised by forcing the wedge B under it. The angle of friction for all surfaces is 15^o. Determine the necessary force P to initiate upward motion of the load. Neglect the weight of the wedges.

6. A horizontal force of 10kN holds a system of two wedges in equilibrium. Find the maximum load W which the wedge B may support. Take µ = 0.35 for all surfaces.

7.Two blocks A and B are resting against the wall and floor as shown in figure. Find value of P that will hold the system in equilibrium. µ = 0.25 at the floor, µ = 0.3 at the wall, and µ = 0.2 between the blocks.

8.A 100 N uniform ladder AB is held in equilibrium as shown. If µ = 0.15 at A and B, Calculate the range of values of P for which equilibrium is maintained.

9.A ladder shown is 4 m long and is supported by a horizontal floor and vertical wall. The coefficient of friction at the wall is 0.25 and that at the floor is 0.5. The weight of ladder is 30 N. It also supports a vertical load of 150 N at ‘C’. Determine the least value of α at which the ladder may be placed without slipping to the left.