Question

A crane can lift a box of 600 kg mass to a height of 20 m in 2 minutes. Calculate the power at which the crane is operating ?

• A. 1,000 watts.
• B. 6,000 watts.
• C. 60,000 watts.
• D. 240,000 watts.
• E. 1,440,000 watts.

Answer 1

The correct option is A 1,000 watts.

Given : $m=600kg$ $h=20$ m

Time of operation $t=2$ min $=120$ s

Work done in lifting a box $W=mgh=600\times 10\times 20=120000$

Power required $P=\frac{W}{t}=\frac{120000}{120}=1000$ watts