Question

a block A weight of 320N resting on a rough horrizontal floor supports a block B 160 N. The two blcok connecting to a string passing arround a smooth pulley. Determine the horizontal force P that has to be applied on block A so as to just move it towards right.take miu=0.25 at all contact surface and also determine the tension T in the string respectively.

Answer 1

According to Newton's second law, we can writer for a block A

$$P=F_{friction} + T (1)$$

wher P is the horizontal force, T is the tension in the string

Friction force is given by formula

$$F_{friction}=kMg (2)$$

The tension in the string is equal to

$$T=mg (3)$$

We put (2) and (3) in (1):

$$P=kMg + mg (4)$$

In our case we have

M=32 kg, m=16 kg, k=0.25

Using (4) we get:

P=240 N

Using (3) we get:

T=160 N

Answer:

P=240 N

T=160 N