A motorcycle is moving with a velocity of 90 km/hr and takes 5 sec to stop after the break is applied. calculate the force exerted by the brakes on the motorcycles, if its mass along with the rider 200km???

we have, v = 0 m/s , u = 90km/hr = 90 *1000/60*60 = 25 m/s  and t = 5 sec

we know that, v = u + at

                     or  a = (v - u)/t

                     or  a = (0 - 25)/5 = -5 m/s² 

Now, mass of the motorcycle along with rider = 200 kg

we know that, Force = mass*acceleration

       therefore, force = 200kg * (-5m/s² )  = -1000 newton

Hence, the force exerted by the brake is 1000 N .