Question

block of mass mkg is kept on a weighing machine in an elevator if the elevator is retarding upward by a m/s2
the reading of weighing machine is (in kgf)
(1) mg
(2) m(g-a)
(3)m(1-a/g)
(4) m(g + a)
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Answer 1

Answer:

2)m(g-a)

Explanation:

Net Force acts upward with retardation a.Apparent weight- actual weight i.e.

R-mg,provide upward retardation a

-ma=R-mg

mg-ma=R

m(g-a)=R