Inspired By Ninad Sinha
Classical Mechanics
Level
2
An object of mass 10 kg is moving with a velocity of 20 m/s.
It accelerates for 10 sec at 2 m/s square.
Calculate the power.
1000 watts
100 watts
400 watts
600 watts
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1 solution
Final speed = 20 + 2 x 10 = 40 m/ s;
Visualize from graph of v versus t of rectangle plus trapezium plus rectangle:
P = F V = m a d/ t = 10 x 2 x [(1/2)(20 + 40) t]/ t = 20 x 30 = 600 W.
Note: V is taking the average of 20 m/ s and 40 m/ s effectively.