A mass of 75kg is placed on a lift. Find the force exerted by the floor of the lift on the mass when the lift is moving up with constant velocity. ([g = 9.8ms^{-2}])
-
A.
750N -
B.
745N -
C.
735N -
D.
98N
Correct Answer: Option C
Explanation
Net force = Upward force – weight
(ma = F – mg)
With constant velocity, acceleration = 0, therefore, ma = 0
(therefore F = mg = 75 times 9.8 = 735N).