Question

An object is hung from a spring balance attached to the ceiling of an elevator cab. The balance reads 65 N when the cab is standing still. What is the reading when the cab is moving upward (a) with a constant speed of 7.6 m/s and (b) with a speed of 7.6 m/s while decelerating at a rate of 2.4 m/s2

Answer 1

(A) Reading will be 65 N

(B) Net force on the elevator will be 49.076 N

Step-by-step explanation:

We have given the balance force = 65 N

Acceleration due to gravity
`g=9.8m/sec^2`

We know that W=mg

So
`65=m* 9.8`

m = 6.632 kg

(a) In first case as the as the speed is constant so the force on the elevator will be 65 N

(B) In second case as the elevator is decelerating at a rate of
`2.4m/sec^2`

So net acceleration = 9.8-2.4=
`7.4m/sec^2`

So net force on elevator will be = m× net acceleration = 6.632×7.4 = 49.076 N