Question

study a 75kg person stands on a scale in an elevator what does read in n and in kg when the elevator is at rest?

Answer 1

To solve this problem we will use Newton's second law in order to obtain the weight of a person. The second law tells us that

F = ma

Where,

m = mass

a = Acceleration

In this particular case, the acceleration is equal to that exerted by the earth through gravitational acceleration, so if the person's weight is 75Kg and the gravity is $9.8m / s^2$ , the weight of the body will be,

$F_W =mg$

$F_W = (75kg)(9.8m/s^2 )$

$F_W = 735.75N$

When the elevator is at rest this reads 735.75N and 75Kg (The same mass of the person)