A constant retarding force of 50N is apllied to a body of mass 10kg moving initially with a speed of `10ms^(-1)` . The body comes to rest after

Options

A. 2s
B. 4s
C. 6s
D. 8s

Answer

A

Explanation

Here, F=-50N(-ve sign for retardation)
`m=10kg, u=10ms^(-1),v=0`
`As F=ma therefore t=(v-u)/(a)=(0-10ms^(-1))/(-5ms^(2-2))=2s`