Question

1. An escalator is used to move 20 people (60 kg
each) per minute from the first floor of a
departmental store to the second floor at a height
of 5 m. Neglecting friction, the power required is
(Take, g = 10 m/s2)
(1) 100 W
(2) 200 W
(3) 1000 W
(4) 2000 W
​

Answer 1

Answer:

1000 w

Explanation:

beacuse it ia 5 high

Answer 2

1000 W

Explanation:

There are 20 people in escalator and each weigh 60 kg. It means total mass (m) in the lift is 1200kg.

As we know,  

                    ⇒ 20 x 60 kg = 1200 kg

Weight is the force through which we are pulled towards the centre of earth.

So, Force (weight) is equal to mass multiplied by gravity which is given 10 m/s.

                    ⇒ m x g = 1200 x 10

                    ⇒ 12000 N (kg-m/$s^{2}$)

distance between first floor and second floor is 5m.

So, work done per unit time in minutes is equal to force multiplied by distance travelled.

                  ⇒ F x distance ravelled = 12000 x 5

                   ⇒  $\frac{W.D.}{time}$ = 60,000 N per minute = 1000  $\frac{N}{sec.}$

Hence, the power required is 1000 W.