A car of weight 20000 N climbs up a hill at a steady speed of 8 m/s, gaining a height of 120 m in 100 s. Calculate:
(a) work done by the car.
(b) power of engine of car.

Here given, weight of the car $mg=20000\ N$

Height gained by the car $h=120\ m$

Time $t=100\ s$

Speed of the car $v=8\ m/s$
 

(a). Work done by the car to climb $=mgh$

$=20000\ N\times120\ m$

$=2400000\ Joule$

$=2400\ kJ$     [Because $1kJ=1000\ J$]

Therefore, work done by the car is $2400\ kJ$.

(b). Power of the engine $=\frac{work\ done}{time}$

$=\frac{2400000\ J}{100\ s}$

$=24000\ W$

$=24\ kW$    [Because $1\ kW=1000\ Watt$]