Class 9 Chapter 3 Dynamics Physics Notes (With PDF)

Are you looking for Chapter 3 Dynamics Notes in PDF? You are at the right place. You can download the complete exercises, numerical, short questions and MCQs of the unit 3.

KIPS 9th Class Physics notes for Dynamics are here to solve your problems. Do you already the definition? Dynamics is the branch of mechanics concerned with the motion of bodies under the action of forces.

Do you belong to  Federal Board, Lahore Board, Faisalabad Board, Rawalpindi Board, Sargodha Board, Wah Board? Then these notes are helpful.

Title: Dynamics

Chapter: 3rd Chapter of 9th Class Physics

File Size: 5.8 MB

FileType: PDF

Pages: 30


Dynamics 9th Class KIPS Notes



1: Define dynamics.
2: Define force
3: Define inertia
4: What is momentum?
5: State Newton’s First law of motion.
6: Why Newton’s First law of motion ls also of Inertia?
7: State Newton’s Second law of motion
8: What ls the unit of force? Define lt.
9: State Newton’s Third law of motion
10: If a moving body  has no acceleration; does it mean that no force is acting on it?
11: What do you know about Momentum?
12: Prove that l kgms·1 = lNs
13: On which quantities, Momentum (quantity of motion) of a body depend?
14: What is the relationship of momentum and the force applied on the body?
15: State law of conservation of momentum.
16: Write down the advantages and disadvantages of friction?
17: Write down the methods to reduce friction.
18: What is Sliding friction?
19: Why is the rolling friction is less than sliding fricti.on?
20: Suppose you are running and want to stop at once. Surely you will have to produce negative acceleration in your speed. Can you teJI from where does the necessary force come?
21: Define circular motion.
22: Define centripetal force
23: Define centripetal acceleration
24: Define and explain centrifugal force. Is it a reaction of centripetal force?
25: Why outer edge of the road is kept higher than inner edge (banking of road)?
26: Explain the function of the washing machine  (dryer).
27: Explain the function of cream separator.
28: Why a cyclist bend himself toward the inner side of the curved path while taking
a turn with high speed?
29: What is centrifuge? And what is the principle of the centrifuge?
30: Can a body move with uniform velocity in a circle? If not, why?
31: Can a body move along a circle without the centripetal force? .
32: Moon revolves around the earth, from where it gets necessary centripetal force?

The Short Questions With Answers In the Below Images



l: State and Explain Newton’s First law of motion
2: State and Explain Newton’s Second law of motion
3: Differentiate between Mass and Weight.
4: State and Explain Newton’s Third law of motion
5: Explain the  tension in the string.  If two bodies of masses  m1  and m2 are hanging
from the two ends of a string which are passing over a pulley, find the values of tension and acceleration in it.
6: How you can prove that rate of change in momentum of a  body is  equal to the applied force?
7: State and explain Law of Conservation of Momentum.·
8: Define friction. Explain the cause of friction and. derive its mathematical formula.
9: Explain the rolling friction.
10: Explain the roll of friction in Braking and explain the Skidding.
11: Define centripetal  force and centripetal acceleration  and derive the mathematical
the relation for centripetal force and acceleration.

The Long Questions With Answers In Below Images



1. Newton’s first law of motion is valid only in the absence  of:

2. Inertia depends  upon:

3. A boy jumps out of a moving bus. There is a  danger for him to fall:

4. A  string is stretched by two equal and opposite forces of  10N each. The  tension in the string is:

5. The mass of a body

6. Two bodies of masses m1 and m2, attached to the ends of an inextensible string passing over a frictionless pulling such that both  move vertically. The acceleration of the bodies is

7. Which of the following is the unit of momentum?

8. When the horse pulls a cart, the action is on the:

9. Which of the following material lowers friction when pushed between metal plates?

Short Questions

1. Define  the following terms:

i) Inertia

ii) Momentum

iii) Force

iv) Force of friction

v) Centripetal force

2. What is the difference between?

i) Mass and weight

ii) Action and reaction

iii) Sliding friction and rolling friction

3. What is the law of inertia?

4. Why is it dangerous to travel on the roof of a bus?

5. Why does a passenger move outward when a bus takes a turn?

6. How can you relate a force with the change of momentum of a body?

7. What will be the tension in a rope that is pulled from its ends by two opposite forces 100 N each?

8. Action and reaction are always equal and opposite than how does a body move? 

9. A  horse pushes  the cart. If the action and  reaction are equal and opposite  then how does the cart move’?

10. What ls the law of conservation of momentum?

11. Why is the law of conservation of momentum important?

12. When a gun is fired, it recoils.   Why?

13. Describe two situations in which force of friction is needed?

14. How does oiling the moving parts of a machine lower friction?

15. Describe ways to reduce friction.

16. Why rolling friction is less than sliding friction?

The TextBook Questions With Answers In Below Images


1. 20 N force moves a body with an acceleration of 2 ms”2. What is it its mass?
2. The weight of a body is 147 N. What is its mass?
3. How much force is needed to prevent a body of mass 10 kg from falling?
4. Find the acccJeration produced by a force of 100N in a mass of 50 kg.
5. A body has a weight 20 N. How much force is required to move it vertically upwards with an acceleration of 2 ms·2
6. Two masses 52 kg and 48 kg are attached to the ends of a string that pass over a frictionless pulley. Find the tension in the string and acceleration in the bodies.
7. Two masses 26 kg and 24 kg are attached to the ends of a string which pass over a frictionless pulley. 26 kg is lying on a smooth horizontal table. 24 kg mass is moving vertically downward.  Find the tension in the string and the acceleration in the bodies.
8. How much time is required to change 22 Ns momentum by a force of 20 N?
9. How much  is the force of friction  between a  wood block of mass 5  kg and the horizontal marble floor? The coefficient of friction between wood and marble is 0.6
10. How much centripetal force is needed to make a boy of 0.5 kg to move in a circle of radius 50 cm with·a speed of 3 ms”1?

The Numericals With Answers In Below Images


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