Question

ANS. this question...........

Answer 1

Given: Mass of man is 60kg, let it be m1 
           Initial velocity of the man is 18km/hr  which is nothing but 5m/sec, let it            be v1
  
           Mass of the car is 100kg, let it be m2
           Initial velocity of car is 0m/s, let it be v2

To find: Velocity of car with which it will start travelling, let it be v

Sol : According to Newton's LAW OF CONSERVATION OF MOMENTUM
  
        m1*v1 + m2*v2 = {m1+m2}v
     ⇒ 60*5 + 100*0 = {60+100}v
     ⇒ 300/160 = v
     ⇒ v = 1.875 m/s

So the car will start travelling with a velocity of 1.875 m/s