Question

a body of mass 2 kg is suspended in an elevator by means of a spring balance the balance reads its weight when elevator moves up with an acceleration of 5ms_2 as
30.5n b 29.6n c 26.5n d 9.8n

Answer 1

this question is a bit lengthy....

Answer 2

the actual weight of the mass is 20 newtons......first of all..

Answer 3

when the elevator moves upward with an acceleration a = 5 m/s^2 ......then the spring balance will show(give reading) of apparent weight more than the actual weight ..... which means that the choice "d"----9.8 is definitely wrong....

Answer 4

now while the elevator is moving upward with an acceleration ...... there are two forces acting on it ......the upward tension "T" and downward weight "w".....

Answer 5

As the mass "m" along with the elevator are accelerating upward with acceleration "a".....So a net force F=ma is acting in the upward direction ..... this net force F=ma= the difference between T and w. T>W because the elevator+mass are both accelerating upward.

Answer 6

Therefore,
F=ma=T-W
|| ma=T-W
Putting values||
ma=T-mg||
T=ma+mg||
T=m(a+g)||
T=2(5+9.8)||
T=29.6N
As the tension is equal to the apparent weight of the mass being shown by the spring balance....

Answer 7

So option b is the right choice....

Answer 8

Did you understand?