Question

A man of mass 70 kg, stands on a weighing machine in a lift, which is moving
(a) upwards with a uniform speed of 10 ms
(b) downwards with a uniform acceleration of 5 ms
(c) upwards with a uniform acceleration of 5 ms. What would be the reading on the scale in each case..? (d) what wud be the reading if the lift mechanicanism failed and it hurted down free under the gravity..?​

Answer 1

Explanation:

a) as speed is uniform there is no acceleration.

so W = m(g+a)

= m(g)

W = 70×10 = 700 N

b) W = m(g+(-a))

= 70(10-5)

= 70(5) = 350 N

c) W = m(g+a)

= 70(10+5)

= 70(15) =1050 N

d) W = m(g)

= 70×10 = 700 N