Question

A weight W is tied to two strings passing over
the frictionless pulleys A and B as shown in the
figure. If weights P and Q move downwards
with speed v, the weight W at any instant rises
with the speed-
0
1
Q.7
W
w
(1) v cos 0
(2) 2v cos e
(4) 2v/cos e
(3) v/cos​

Answer 1

Answer:

The answer will be option 3 v/cosθ

Explanation:

The diagram is attached with the answer and it is done accordingly.

According to the problem both P and Q move downwards with speed v

and the length of the of string is l

let u be the rise of speed,

therefore,

v= dl/dt

and according to the diagram l^2= h^2+ x^2

Now if we differentiate both side with respect of time,

we get,

2l(dl/dt)= 2h (dh/dt)+ 0

2lv= 2hu

=> u= lv/h

=> u= v/h/l

=> u= v/cosθ

Answer 2

thank you......

it's your answer......