Chapter Exam

Chapter 8: Force and Laws of Motion — Online MCQ Test

Q: Which of the following is a vector quantity?

Answer: B. Force — Force has both magnitude and direction, so it is a vector quantity. Mass, speed, and time are scalar quantities.

Q: The SI unit of momentum is:

Answer: A. kg m/s — Momentum equals mass × velocity, so its unit is kg × m/s = kg m/s.

Q: A force of 10 N acts on a body of mass 2 kg. The acceleration produced is:

Answer: B. 5 m/s² — Using F = ma, acceleration = F/m = 10/2 = 5 m/s².

Q: A body of mass 4 kg moving with velocity 3 m/s has momentum equal to:

Answer: B. 12 kg m/s — Momentum is mass × velocity = 4 × 3 = 12 kg m/s.

Q: A 2 kg cart moving at 6 m/s collides with a stationary 1 kg cart and they move together after collision. If momentum is conserved, their common velocity is:

Answer: A. 2 m/s — Initial momentum = 2 × 6 + 1 × 0 = 12 kg m/s. Combined mass = 3 kg, so velocity = 12/3 = 4 m/s.

SCIENCE · CLASS 9th · Karnataka State Board

Practice Chapter 8: Force and Laws of Motion with a free chapter-wise online MCQ test for Karnataka State Board CLASS 9th SCIENCE. This chapter covers: This chapter details balanced unbalanced forces Newton three laws of motion inertia mass momentum and conservation of momentum principles.. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 8: Force and Laws of Motion — Important Questions & Answers (FAQ)

Frequently asked questions from Karnataka State Board CLASS 9th SCIENCE — Chapter 8: Force and Laws of Motion, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which of the following is a vector quantity?

A. Mass
B. Force ✓
C. Speed
D. Time

Answer: B. Force
Force has both magnitude and direction, so it is a vector quantity. Mass, speed, and time are scalar quantities.

The SI unit of momentum is:

A. kg m/s ✓
B. N/m
C. kg/m
D. N s/m

Answer: A. kg m/s
Momentum equals mass × velocity, so its unit is kg × m/s = kg m/s.

A force of 10 N acts on a body of mass 2 kg. The acceleration produced is:

A. 2 m/s²
B. 5 m/s² ✓
C. 8 m/s²
D. 20 m/s²

Answer: B. 5 m/s²
Using F = ma, acceleration = F/m = 10/2 = 5 m/s².

A body of mass 4 kg moving with velocity 3 m/s has momentum equal to:

A. 7 kg m/s
B. 12 kg m/s ✓
C. 1.33 kg m/s
D. 24 kg m/s

Answer: B. 12 kg m/s
Momentum is mass × velocity = 4 × 3 = 12 kg m/s.

A 2 kg cart moving at 6 m/s collides with a stationary 1 kg cart and they move together after collision. If momentum is conserved, their common velocity is: