Q.

A body of mass 2 kg begins to move under the action of a time dependent force given by F→=(6ti^+6t2j^)N. The power developed by the force at the time t is given by:

1 (6t4+9t5) W  
2 (3t3+6t5) W  
3 (9t5+6t3) W  
4 (9t3+6t5) W  

Ans.

(4)

F→=(6ti^+6t2j^) N

F→=ma→=(6ti^+6t2j^)

a→=F→m=(3ti^+3t2j^)

v→=∫0ta→ dt=3t22i^+t3j^

P=F→·v→=(9t3+6t5) W