12.A car moving with a speed of 20m/s can be stopped by applying brakes, after travelling a distance of 2m.The retardation of the car is
solution: car is moving with a speed(u)=20m/s it can stopped by brakes ,that means final velocity (v)=0 in mean time ,it travelled a distance (S)=2m. by given information ,initially it has initial velocity and then comes rest .so, the car is in retarded motion. we have the formula, V2-u2=2aS 0-(20)2 =2a(2) -400=4a a=-100m/S2 The car …