An object of mass 1 kg travelling in a s | Class 9 Science Chapter Force and Laws of Motion, Force and Laws of Motion NCERT Solutions

Question:

An object of mass 1 kg travelling in a straight line with a velocity of 10 m s-1 collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.

Answer:

Mass of the object, m1 = 1 kg

Mass of the wooden block, m2 = 5 kg

Velocity of the object before collision, v1 = 10 m/s

Velocity of the wooden block before collision, v2 = 0 m/s

Total mass of the combined system = m1 + m2 = 1 + 5 = 6 kg

∴ Total momentum before collision = m1 v1 + m2 v2

= 1 (10) + 5 (0) = 10 kg m s−1

Velocity of the combined object = v

Momentum = total mass x velocity of combined object

= (m1 + m2) v = 6v

According to the law of conservation of momentum:

Total momentum before collision = Total momentum after collision

m1 v1 + m2 v2 = (m1 + m2) v

10 = 6 v

The total momentum after collision is also 10 kg m/s.

Hence, velocity of the combined object after collision = 


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Force and Laws of Motion.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Comments

Comment(s) on this Question

Welcome to the NCERT Solutions for Class 9 Science - Chapter . This page offers a step-by-step solution to the specific question from Excercise 3 , Question 15: An object of mass 1 kg travelling in a straight line with a velocity of 10 m s-1 collides with,....