Q.

A sand dropper drops sand of mass m(t) on a conveyer belt at a rate proportional to the square root of speed (v) of the belt, i.e., dmdtv. If P is the power delivered to run the belt at constant speed then which of the following relationship is true          [2025]

1 P2v3  
2 Pv  
3 Pv  
4 P2v5  

Ans.

(4)

Power = F·v and F=dpdt=Rate of change of linear momentum

              F=v·dmdt=Kv3/2, K is constant

Power (P)=(Kv)3/2·(v)=Kv5/2

So, P2v5