A person of 60 kg mass is in a lift which is coming down such that the man exerts a force of 150 N on the floor of the lift. Then the accelaration of the lift is `(g = 10 ms^(-2))`

Options

A. `7 . 7 ms^(-2)`
B. `40 . 0 ms^(-2)`
C. `22.5 ms^(-2)`
D. `15. 0 ms^(-2)`

Answer

A

Explanation

Mass of person , m = 60 kg
Force on floor of lift , F =150 N
As lift is coming down the resultant acceleration
`a.= (g + a)`
Using Newton.s force law
f = ma.
150 = 60 (10 + a)
` 10 + a = (150)/(60)`
2 . 5
`a = - 75 m//s^(2)`
`|a| = 7.5 m//s^(2)`