# blocks and pulley

## Problem 511 | Friction

**Problem 511**

Find the least value of P required to cause the system of blocks shown in Fig. P-511 to have impending motion to the left. The coefficient of friction under each block is 0.20.

## Problem 510 | Friction

**Problem 510**

What weight W is necessary to start the system of blocks shown in Fig. P-510 moving to the right? The coefficient of friction is 0.10 and the pulleys are assumed to be frictionless.

## Problem 509 | Friction

**Problem 509**

The blocks shown in Fig. P-509 are connected by flexible, inextensible cords passing over frictionless pulleys. At A the coefficients of friction are μ_{s} = 0.30 and μ_{k} = 0.20 while at B they are μ_{s} = 0.40 and μ_{k} = 0.30. Compute the magnitude and direction of the friction force acting on each block.