Question

A large fish hangs from a spring balance supported from the roof of an elevator.

a) If the elevator has an upward acceleration of 2.45m/s2 and the balance reads 70.0N , what is the true weight of the fish?
b) Under what circumstances will the balance read 35.0N ?
c) What will the balance read if the elevator cable breaks?

Answer 1

Step-by-step explanation:

a) As the elevator ACCELERATES upward, this accel is added to the accel of gravity , thus affecting the weight of the fish

F = ma

70 N = m ( 9.81 + 2.45) m/s^2

m = 5.71 kg so the ACTUAL weight = ma = 5.71 kg * 9.81 m/s^2 = 56N

b) when the elev is accelerating downward

F = ma

35.0 = 5.71 kg ( 9.81 - e)

e = accel of elevator = 3.68 m/s^2 DOWNWARD

c) If you are in free fall the scale will read 0 N

( you and your fish are weightless)