A spring balance,which is suspended from the roof of a lift, carries a mass of 1kg at its free end. If the lift accelerates upwards at 2.5ms-2, determine the reading on the spring balance. [g = 10ms-2]
-
A.
24.0N -
B.
12.5N -
C.
7.5N -
D.
4.0N
Correct Answer: Option B
Explanation
F = ma
= 1 x 2.5 = 2.5N
weight = mg = 1 x 10 = 10N
Reading = F + Wt = 2.5 + 10
= 12.5N