Physics - W.E.P. Question with Solution | TestHub

PhysicsW.E.P.PowerEasy2 minPYQ_2020

PhysicsEasynumerical

Power applied to a particle varies with time as $P = (3 t^{2} - 2 t + 1)$ watt, where $t$ is in second. What is the change in its kinetic energy (in joule) between $t = 2 s$ and $t = 4 s$ ?

Answer:

46.00

Solution:

$P = 3 t^{2} - 2 t + 1 = \frac{d E}{d t}$

$∴ d E = (3 t^{2} - 2 t + 1) d t$

$E = \int_{t = 2 s}^{t = 4 s} (3 t^{2} - 2 t + 1) d t$

$= {[\frac{3 t^{3}}{3} - \frac{2 t^{2}}{2} + t]}_{t = 2 s}^{t = 4 s}$

$= [(4^{3} - 2^{3}) - (4^{2} - 2^{2}) + (4 - 2)]$

$E = 56 - 12 + 2 = 46 J$

Stream:JEESubject:PhysicsTopic:W.E.P.Subtopic:Power

⏱ 2mℹ️ Source: PYQ_2020

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