A body of weight 10N in lift which is moving upward with acceleration 2g its weight will be?

1 Answer

#30\ N#

Explanation:

The weight #W# of a body of mass #m# is the normal reaction offered by the base supporting the body against the acceleration due to gravity #g# which is given as

#W=mg#

#mg=10\ N# (given in the question)

#m=10/g#

Now, when the lift accelerates with an acceleration #a=2g# in vertical upward direction then the normal reaction #R_N# offered by the base of the lift on the body will be the effective weight of body during upward motion .

Considering the body as the system & applying Newton's second law

#F_{\text{net}}=ma#

#R_N-W=ma#

#R_N=W+(10/g)(2g)\ \quad (\because a=2g)#

#R_N=10+20#

#R_N=30\ N#

The reaction offered by the base of lift on the body is #R_N=30\ N#

hence the effective weight experienced by the body during upward motion will be #30\ N#