A crane lifts weight of 75 kg to a height of 15 m in 15 s . The power of the crane is (assuming g=9.8 m/s2 )

Question

A crane lifts weight of 75 kg to a height of 15 m in 15 s . The power of the crane is (assuming g=9.8 m/s2 ) (A)  635 W  (B)  735 W  (C)  835 W  (D)  1135 W

Tardigrade Admin · Accepted Answer

Work done by lift = change in PE of weight =mgh =750× 9.8× 15=11025 J So power of crane =( textEnergy used/ texttime) =(11025/15)=735 W

Q. A crane lifts weight of $75 k g$ to a height of $15 m$ in $15 s$ . The power of the crane is (assuming $g = 9.8 m / s^{2}$ )

$635 W$

$735 W$

$835 W$

$1135 W$

Work done by lift = change in PE of weight
$= m g h$ $= 750 \times 9.8 \times 15 = 11025 J$
So power of crane
$= \frac{Energy used}{time}$
$= \frac{11025}{15} = 735 W$

Q. A crane lifts weight of 75kg to a height of 15m in 15s . The power of the crane is (assuming g=9.8m/s2 )

635W

735W

835W

1135W