0 votes
349 views
in Physics Form 3 by

A car of mass 2000kg travelling at 5ms−1 collides with a minibus of mass 5000kg travelling in the opposite direction at 7ms−1. The vehicles stick and move together after collision. If the collision lasts for 0.1seconds;

  1. Determine the velocity of the system after collision of 3 decimal places. 
  2. Calculate the impulsive force on the minibus 
  3. Calculate the change in kinetic energy of the system 
  4. Explain the change in kinetic energy of the system 

1 Answer

0 votes
by
  1. Momentum before collision = momentum after collision 
    M1U1 +M2 (−U2) = (M+ M2) V
    (2000 x 5)2 +5000 x (−7) = 7000V  
    V = −25000
            7000
    = −3.571 ms−1 
  2. Ft = M(V−U)
    f = m(V−U)     
              t
    F = 5000 ( −3.571 − (−7)  
                             0.1
    F = 171,450 N 
  3. initial K.E = ½ M1U12 + ½ M2 (−U2)2
    = ½ x 2000 X 52 + ½ x 5000 x (−7)2
    = 25,000 + 122, 500
    = 147,500J  
    final K.E + ½ (M+M2) V2
    = ½ (2000 + 5000) (−3.571)2
    = 44,632 J  
    Change in K.E = K.E lost − final K.E − Initial K.E
    = (44,632 − 147,500) J
    = −102,868J 
  4. The change /lost K.E is converted into heat, sound, light and spent in deformation

Related questions

Welcome to EasyElimu Questions and Answers, where you can ask questions and receive answers from other members of the community.

5.4k questions

5.8k answers

8 comments

590 users

...