Question

If the velocity 5 kg object become 90k/h from 72km/h after 10 second then find out (i) work done (ii) power

Answer 1

(i)Work done=ΔKinetic energy

mass=5kg

initial velocity=72km/h     ⇒ 20m/s

final velocity=90km/h      ⇒25m/s  

CHANGE IN KE  $=\frac{1}{2}mv^2-\frac{1}{2}mu^2$

=$\frac{1}{2} (5)(25)^2-\frac{1}{2} (5)(20)^2$

=562.5 Joules

(ii)power=$\frac{dW}{dt}$

=W=562.5 Joules

=562.5/10   ⇒ 56.25 Joules/sec

hope it helps...

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