Q.

An object of mass 1000 g experiences a time dependent force F→=(2ti^+3t2j^)N. The power generated by the force at time t is:        [2025]

1 (2t3+3t3)W  
2 (2t2+18t3)W  
3 (3t3+5t5)W  
4 (2t3+3t5)W  

Ans.

(4)

m = 1000 gram = 1 kg

F→=(2ti^+3t2j^)

dvdt=Fm=(2ti^+3t2j^)

⇒ ∫0vdv=∫0t(2ti^+3t2j^)dt

⇒ v→=t2i^+t3j^

Power, P=F→·v→

P=(2ti^+3t2j^)·(t2i^+t3j^)

P=(2t3+3t5)W