Question 45

A block of mass 10 kg accelerates uniformly from rest to a speed of 2 nits in 20 s. The average power developed in time interval of 0 to 20 seconds is :

Solution

A block of mass 10 kg accelerates uniformly from rest to a speed of 2 m/s in 20 s.

$$ Power = \frac{Work}{Time} $$

Here work will be the kinetic energy of the block

i.e $$ = \frac{1}{2}\times Mass \times Velocity^2$$

$$= 0.5\times 10 \times 2^2$$

$$=20 J$$

$$Power = \frac{20}{20} = 1W$$

Option D is correct.

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