Question

When a lift is moving upward with acceleration of 5 m/s2 then percentage change in the weight of the personin the lift is x%. If the lift is moving down with acceleration 5 m/s2 then percentage change in the weight ofsame person is y%. Then the ratioyx is (g = 10 m/s2)

Answer 1

Answer:

y ratio x is 1:1

Explanation:

Let the mass of the person be m

When a person is inside the lift and the lift is moving up with an acceleration a m/s² then the person will feel her weight increase by ma.

Therefore net weight is

W = m(g + a)

When a person is inside the lift and the lift is going down with an acceleration a m/s² then the person will feel her weight decrease by ma.

Therefore net weight is

W' = m(g - a)

Here,  a = 5 m/s²

Change in the weight of the person when the lift is moving up

= m(g + a) - mg = ma

Percentage change in the weight of the person when the lift is moving up

x = (ma/mg) × 100 = 100a/g           .............. (1)

Similarly percentage change in the weight of the person when the lift is moving down

y = (ma/mg) × 100 = 100a/g           .............. (2)

From equation (1) and (2)

x = y

or, y:x = 1:1