Hello!!!!

Hope you are doing great!!!!

Initial speed =u=36km/h=10m/s

final speed =v= 0m/s

time t=4sec

Mass of the three wheeler m=400kg

mass of the driver=m'=65 kg

Total mass=400+65=465kg

v=u+at

a=v-u/t

=0-10/4

=-2.5m/s^2

The negative sign indicates that the velocity of the three wheeler is decreasing with time.

F=Ma

=465*-2.5

= -1162.5 N

The negative sign indicates that the force is acting against the direction of motion of the three wheeler.

Hope it helps!!!!