# The elevator lifted several people 20 meters. at the same time, a work of 42kJ was performed.

**The elevator lifted several people 20 meters. at the same time, a work of 42kJ was performed. How many people have lifted the lift if the weight of each of them can be considered equal to 700 N?**

h = 20 m.

g = 10 N / kg.

A = 42 kJ = 42000 J.

P1 = 700 N.

n -?

The mechanical operation of elevator A is determined by the formula: A = m * g * h, where m is the mass of all passengers, g is the acceleration of gravity, h is the lift height.

m = n * m1, where n is the number of passengers, m1 is the mass of one passenger.

A = n * m1 * g * h.

The product of the passenger’s mass m1 and the gravitational acceleration g will be his weight p1: P1 = m1 * g.

A = n * P1 * h.

The number of passengers will be determined by the formula: n = A / P1 * h.

n = 42000 J / 700 N * 20 m = 3.

Answer: there were n = 3 passengers in the elevator.