Question

A man is throwing bricks of mass 2 kg onto a floor from a height of 2 m. Bricks reach the floor at a speed `2sqrt(10)` m/s. Man throws 10 bricks in a minute. If the power of man is W watt then `3/10` W is equal to ______ W.

विकल्प

• 1.22

• 1.33

• 1.44

• 1.55

Answer 1

A man is throwing bricks of mass 2 kg onto a floor from a height of 2 m. Bricks reach the floor at a speed `2sqrt(10)` m/s. Man throws 10 bricks in a minute. If the power of man is W watt then `3/10` W is equal to 1.33 W.

Explanation:

Work done by man on bricks,

= `n(mgh + 1/2mv^2)`

∴ P = `(10(2 xx 10 xx 2 + 1/2 xx 2 xx (2sqrt(10))^2))/60`

= `40/3` W