View and Download the solved questions, solved numerical problems or 9th Class Physics notes of Chapter 3 “Dynamics” of Punjab Textbook Board. These 9th class physics notes of 3rd Chapter are according to the new syllabus (2013) of Punjab Boards including Lahore Board, Gujranwala Board, Sahiwal Board, Rawalpindi Board, Faisalabad Board, Multan Board, Bahawalpur Board, Federal Board, DG Khan Board and Sargodha Board. Students of 9th Class of all these board can facilitate from the physics notes given below. You can also download 9th Class Physics Chapter 3 Solved Questions and Numericals Problems.

### Unit 3: Dynamics

By studying this chapter students will be able to: Define momentum, force, inertia, friction and centripetal force. Solve problems using the equation Force = change in momentum / change in time. Explain the concept of force by practical examples of daily life. State Newton’s laws of motion. Distinguish between mass and weight and solve problems using F= ma, and w = mg. Calculate tension and acceleration in a string during motion of bodies connected by the string and passing over frictionless pulley using second law of motion. State the law of conversation of momentum. Use the principle of conservation of momentum in the collision of two objects. Determine the velocity after collision of two objects using the law of conversation of momentum. Explain the effect of friction on the motion of a vehicle in the context of tyre surface, road conditions including skidding, braking force. Demonstrate that rolling friction is much lesser than sliding friction. List various methods to reduce friction. Explain that motion in a curved path is due to a perpendicular force on a body that changes direction of motion but not speed. Calculate centripetal force on a body moving in a circle. State what will happen to you while you are sitting inside a bus when the bus

1. Starts moving suddenly
2. Stops moving suddenly
3. Turns a corner to the left suddenly

Write a story about what may happen to you when you dream that all frictions suddenly disappeared. Why did your dream turn into a nightmare?