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Power Produced by Time Dependent Force on Moving Body

A body of mass 2 kg2\text{ kg} begins to move under the influence of time dependent force F=(2ti^+6t2j^) N\vec{F} = (2t\hat{i}+6t^2\hat{j})\text{ N}, where i^\hat{i} and j^\hat{j} are unit vectors along xx and yy-axis respectively. The power produced by the force at t=2 st = 2\text{ s} is ______ W\text{W}.

Official Numerical Answer200

Topics & Concepts

Step-by-Step Solution

Given the force F=2ti^+6t2j^\vec{F} = 2t\hat{i} + 6t^2\hat{j} acting on a body of mass m=2 kgm = 2\text{ kg} starting from rest, the acceleration is a(t)=Fm=ti^+3t2j^\vec{a}(t) = \frac{\vec{F}}{m} = t\hat{i} + 3t^2\hat{j}. Integrating acceleration gives the velocity vector v(t)=t22i^+t3j^\vec{v}(t) = \frac{t^2}{2}\hat{i} + t^3\hat{j}. The instantaneous power P(t)=Fv=t3+6t5P(t) = \vec{F} \cdot \vec{v} = t^3 + 6t^5. Evaluating at t=2 st = 2\text{ s} yields P(2)=23+6(25)=8+192=200 WP(2) = 2^3 + 6(2^5) = 8 + 192 = 200\text{ W}.

Power Produced by Time Dependent Force on Moving Body | Physics PYQ Solution - JEE Challenger