A motor car of mass 300 kg is moving with a velocity of 25 `ms^(-1)`, by applying brakes the car was brought to rest in a distance of 15 m. The force of retardation in Newton is

Options

A. 2500
B. 4500
C. 6250
D. 7500

Answer

C

Explanation

`m = 300 kg, u = 25 ms^(-1) ,s = 15 m, v = 0 (Given)`
` v^(2) = u^(2) - 2as`
` implies 0=(25)^(2)-2xxaxx15`
`implies 30a=625`
`therefore a=625/30 ms^(-2)`
Force of retardation F=ma