A lift in an office building moves vertically with different accelerations while an engineer stands on a weighing machine inside it. The engineer’s actual mass is 70kg.
a. (i) Define the term ‘weight’ of a body near the Earth’s surface.
b. (ii) Derive an expression for the reading shown by the weighing machine when the lift is moving upward with an acceleration a.
c. (iii) When the lift starts from rest and acquires an upward acceleration of 2.0ms−2, what reading will the engineer observe on the machine?
d. (iv) State the reading when the lift moves downward with the same magnitude of acceleration.