A body of mass 1 kg begins to move under the action of a time dependent force \(\vec{F}\) = (2t î + 3t2 ĵ) N, where î and ĵ are unit vectors along x and y axis. What power will be developed by the force at the time t?
Answer & explanation
Correct answer: option 4
\(\vec{F} = m \vec{a}\)
m = 1 kg
⇒ \(\vec{a} = [2t î + 3t^2 ĵ] m/s^2 = \frac{d\vec{v}}{dt} \)
\(\vec{v} = t^2 \hat{i}+ t^3 \hat{j} \)
\(\vec{F} = \) (2t î + 3t2 ĵ) N
P = \(\vec{v}.\vec{F}\)
= \(2t^3 \hat{i}+ 3t^5 \hat{j} \)