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A body of mass 1 kg begins to move under the action of a time dependent force F→ = (2tî + 3t2ĵ) N, where î and ĵ are unit vectors alogn x and y axis. What power will be developed by the force at the time t?
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- (2t2 + 3t3)W
- (2t2 + 4t4)W
- (2t3 + 3t4) W
- (2t3 + 3t5)W
Correct Option: D
Given force F→ = 2tî + 3t2ĵ
According to Newton's second law of motion,
m | = 2tî + 3t2ĵ (m = 1 kg) | |
dt |

⇒ v→ = t2î + t3ĵ
Power P = F→ . v→ = (2tî + 3t2ĵ) . (t2î + t3ĵ)
= (2t3 + 3t5)W