Calculate the height through which a crane can lift a load of 4T when its motors operates at 4 HP for time 10 seconds.[g=10 m/s², 1 HP = 750 W]?

Power of the motor = 4 HP = 4 x 750 W = 3000 W

Time for which it was run = 10 s

Energy consumed by the motor in this time = 3000 × 10 = 3 × 10⁴ J
This energy is used to lift 4T load to height 'h'.

E = mgh
h = E/mg
 $h=\frac{E}{mg}=\frac{3\times {10}^{4}J}{\left(4000kg\right)\left(10\right)}=\frac{3\times {10}^{4}J}{\left(40000\right)}=0.75 m$
Regards