Question

A car is moving with velocity 108km/h.if driver of the car want to change its velocity from 108km/h to 90km/h in two minutes.mass of the car is 300kg.ehat force applied by the brakes on the tyres?​

Answer 1

change velocity into m/s

v = u +at

25 = 30 + a(120)

a = -5/120 = -1/24

force = ma = 300 × 1 / 24 = 12.5 N

hope it helps

Answer 2

Answer:

-12.5 N

Explanation:

initial velocity U =  108 km/h   or   30 m/s   (108 * 5/ 18)

final velocity V   =   90 km/h    or    25 m/s   (90  * 5/ 18)

time               T   =    2 min           or    120 seconds

mass             M  =    300 kg

Force applied F =ma

here u should find  a (acceleration) by using the below formula:

                     v   = u + a*t

as we know that

                 25 = 30 + a *120

                -5   = a*120

                -5/ 120 = a

               -1 / 24   = a

                        F  = m * a

                            = 300 * (-1 / 24)

                            = -12.5 N