Question

The pulley moves up with a velocity of $10m/s$. Two blocks are tied by a string which passes over a pulley. The velocity $V$ will be ___________. Given $v_b=5m/s\downarrow$

• A. $5m/s\uparrow$
• B. $25m/s\uparrow$
• C. $15m/s\uparrow$
• D. $35m/s\uparrow$

Answer 1

The correct option is B $25m/s\uparrow$

From fig. block which has 5 m/s velocity.

Since it has velocity 5 m/s downward and pulley is moving with 10m/s upward then the block is actually moving downward with velocity 15m/s with respect to pulley. And hence the other block will be moving with velocity 15m/s upward with respect to pulley.But if someone look at the system from anywhere except the pulley then it will see that the block is moving with $(15+10)=25m/supward$