Question

With what acceleration must the brakes be applied to stop a vehicle travelling with a speed of 40km/hrs within 20 sec? ​

Answer 1

first convert 40km/h into m/s.

it is (100/9) m/s

then use formula v= u +at

by using it we get acceleration, a=-5/9 m/s^2

negative sign shows that it is retarding motion