** Class 9 Science MCQ Chapter 9 Force and Laws of Motion**,

**,**

**Class 9 Science MCQ Question Answer****to each chapter is provided in the list of**

**Class 9 Science Multiple Choice Question Answer****SCERT Science Class 9 Objective Types Question Answer**so that you can easily browse through different chapters

**and select needs one.**

**Class 9 Science MCQ Chapter**

**can be of great value to excel in the examination.**

**Question Answer****9 Force and Laws of Motion**## SCERT Class 9 Science MCQ Chapter 9 Force and Laws of Motion

**SCERT** **Class 9 Science MCQ Chapter 9 Force and Laws of Motion Notes** covers all the exercise questions in ** SCERT** Science Textbooks. The NCERT

**Class 9 Science MCQ Chapter**provided here ensures a smooth and easy understanding of all the concepts. Understand the concepts behind every chapter and score well in the board exams.

**9 Force and Laws of Motion****Force and Laws of Motion**

**Chapter – 9**

**Multiple Choice Questions & Answers**

**1. An object gains motion by –**

**(a) gravitation **

**(b) momentum **

**(c) balanced force **

**(d) unbalanced force**

Ans: (d) unbalanced force.

**2. A fan is moving on. Switch off the fan but the fan is moving continue for sometimes, what is the reason?**

**(a) momentum **

**(b) unbalanced force **

**(c) inertia **

**(d) balanced force**

Ans: (c) inertia.

**3. Amoving car is braked suddenly, the passengers bend infrared. What is the reason –**

**(a) inertia**

**(b) for momentum conservation **

**(c) momentum**

**(d) unbalanced force **

Ans: (a) inertia.

**4. Two force acting on a wooden block. But the block has no moved. Then the force is –**

**(a) unbalanced force**

**(b) balanced force**

**(c) force is equal to zero **

**(d) for inertia **

Ans: (b) balanced force.

**5. All planets must orbit the sun. It was firstly provided by – **

**(a) Newton **

**(b) Kepler**

**(c) Galileo Galili **

**(d) copernicus**

Ans: (c) Galileo Galili.

**6. From observation of Galileo Galili, four small bodies orbiting –**

**(a) Jupiter **

**(b) earth**

**(c) moon **

**(d) sun**

Ans: (a) Jupiter.

**7. Safety belts are worn to prevent –**

**(a) collision **

**(b) speed**

**(c) save driver **

**(d) accident**

Ans: (d) accident.

**8. An object is the mass of 10 kilogram. The inertia of the object is –**

**(a) 20kg **

**(b) 10kg**

**(c) 5kg **

**(d) 15kg**

Ans: (b) 10kg.

**9. An objects is mass of 10kg. It moves with 10ms¹ velocity. Then the momentum is –**

**(a) 100 mkg⁻¹ **

**(b) 20kgms⁻¹**

**(c) Okgms⁻¹ **

**(d) Imkg⁻¹**

Ans: (a) 100 mkg⁻¹

**10. An object is mass of 10kg. It moves with 10ms⁻² accelerated. Then the force is –**

**(a) 100 Newton **

**(b) 20 Newton **

**(c) 0 Newton **

**(d) 1 Newton **

Ans: (a) 100 Newton.

**11. What is the S. I. unit of momentum? **

**(a) Kgms⁻² **

**(b) Kgms⁻¹**

**(c) Kgms **

**(d) Kgms² **

Ans: (b) Kgms-¹.

**12. What is the value of In?**

**(a) 1kg * 1 ns⁻¹ **

**(b) 1kg x 1ms⁻²**

**(c) 1kg x 1 n X **

**(d) 1kg × 1m⁻¹ **

Ans: (b) 1kgx1ms-²

**13. One of the law of motion is called law of inertia. Which is it? **

**(a) 1st law of motion **

**(b) 2nd law of motion**

**(c) 3rd law of motion **

**(d) All of the above **

Ans: (a) 1st law of motion.

**14. As the Sailor jumps is forward direction the boat moves backward. It is the example of Newton, s **

**(a) 1st law of motion **

**(b) 2nd law motion **

**(c) third law motion **

**(d) inertia**

Ans: (c) third law motion.

**15. If (mAuA + mB + uB) is the total momentum of the two balls A and B at before the collision and (mAvA + mBvB) is the total momentum after the cellusion. **

**Then which is correct in the following. **

**(a) mAuB = mAvA X mBvB **

**(b) mAuA-mBuB = mAvA-mBvB **

** mAuA mAvA**

**(c) ———— = ————**

** mBuB. mBvB**

**(d) mAuA + mBmB = mAvA + mBvB **

Ans: (d) mAuA + mBmB = mAvA + mBvB .

**16. If (mAuA + mBuB) and (mAvA + mBvB) are the total momentum before the collision and after the collision respectively of the two ball A and B. Then mAuA + mBuB = mAvA+mBvB. It is called – **

**(a) Newton’s 2nd law of motion**

**(b) the law of conservation of momentum**

**(c) momentum**

**(d) momentum**

Ans (b) the law of conservation of momentum.

**17. If force F, mass m and acceleration a, then Newton’s 2nd law’s mathematical representation is-**

**(a) F = m + a**

** m**

**(b) F = ——–**

** a**

**(c) F = ma**

**(d) F = m-a**

Ans: (c) F = ma.

**Very Short Answer Type Questions**

**1. What do you mean by balanced forces?**

Ans: A matter is pulled from both the sides with equal forces, the block will not move. Such forces are called balanced forces.

**2. What do you mean by unbalanced force?**

Ans: A matter is pulled from both or one side unequal forces, the block will move. Such forces are called unbalanced force.

**3. When does a matter gain to move? **

Ans: When the unbalanced force acts the matter.

**4. State the first law of motion.**

Ans: An object remains is a state of rest or of uniform motion is a straight line unless compelled to change that by an applied force.

**5. What is called inertia?**

Ans: The tendency of undisturbed objects to stay at rest or to keep moving with the the some velocity is called inertia.

**6. Give an example of rest inertia.**

Ans: When we are standing is a bus and the bus begins to move suddenly. We tend to fall back ward.

**7. Give an example of moving inertia? **

Ans: A moving car, if it breaks suddenly, the passengers body goes forward same direction.

**8. Who invented pendulum clock? **

Ans: Galileo-galice.

**9. What is the measure of inertia? **

Ans: The mass of an object is a measure of its inertia.

**10. Whose inertia is more between train and cart?**

Ans: The inertia of train is more. Because the train has more mass than cart. momentum?

**11. What is called momentum?**

Ans: The product of mass and velocity is called momentum.

**12. Write the mathematical expression of momentum.**

Ans: Momentum p, the mass m, and velocity v, the p = mv

**13. Write S. I. unit of momentum? **

Ans: Kilogram-metre per second (kgms⁻¹)

**14. State the 2ⁿᵈ law of motion.**

Ans: The rate of change of momentum of an object is proportional to the applied unbalanced force is the direction of force.

**15. Write the mathematical expression of 2ⁿᵈ law of motion.**

Ans: Force F, mass m and acceleration at the according to.2nd law of motion is F = ma.

**16. What is the S. I. unit of force? **

Ans: Newton or Kg Ms⁻²

**17. What is the symbol of Newton? **

Ans: N.

**18. When is the equal value of initial velocity and final velocity? **

Ans: When

Force, F = 0.

**19. Find the force, when 2 kg mass moving with at 5ms⁻² accelerating?**

Ans: F: = ma

= 2 × 5ma²

10 Newton.

**20. Find the force, when 4 kg mass moving with at 2ms-² accelerating?**

Ans: F = ma

= 4kg x 2ms⁻²

= 8 Newton.

**21. State the third law of motion?**

Ans: To every action there is an equal and opposite direction.

**22. Give an example of third law of motion.**

Ans: As the sailor jumps is forward direction the boat moves ard.

**23. Write the law of conservation of momentum.**

Ans: The sum of momenta of th two objects before collision is equal to the sum of momenta after the collision provided there is no external unbalanced force acting them.

**24. An object mass of m, moves with velocity v.What is the momentum. **

Ans : mv.

**25. An object mass of 2 kg moves with velocity 5ms⁻¹ What is the momentum of the object?**

Ans: P = mv

= 2 × 5ms⁻¹

= 10 kgms⁻¹

**26. What do you mean by momenta?**

Ans: Momenta is the plural form of momentum.