Question

An electric motor in a crane while lifting a load produces a tension of $4000N$ in the cable attached to the load. If the motor is winding the cable at the rate of $3m{s}^{-1}$, the power of the motor expressed in $kilowattunits$ must be:

• A. $4$
• B. $3$
• C. $12$
• D. $6$

Answer 1

Answer: (C)

$12$

Power $=F.v$$=4000\times 3$$=12kw$