Ch 3 Physics Class 9
Important easy to understand Notes of Ch 3 Physics Class 9 English Medium written by Professor Sulman Arif Suib. These notes are very helpful in the preparation of Physics for students of the 9th class Physics English Medium and these are according to the paper patterns of all Sindh Book Boards.
Summary and Contents:
Topics which are discussed in the notes are given below:
- Define force. Give its formula and unit.
- Define Momentum with SI unit.
- State and Explain law of conservation of momentum.
- What is Inertia? State Newton's first and third law of motion.
- State Newton's second law of motion. Show the relationship between applied force and the acceleration produced in the body.
- Enumerate at least three clear differences between Mass and Weight.
- Draw a figure showing the direction of a centripetal force, centrifugal force and velocity of an object along a circular path.
- Differentiate between centripetal force and centrifugal force.
- List down some purposeful uses of a centrifuge that humans are benefiting everyday.
- What is friction what is the force of friction? Explain with two examples from daily life.
- Discuss the types of friction: (i) Static Friction (ii) Kinetic Friction (iii) Sliding Friction (iv) Rolling Friction.
- Give some advantages of friction.
- Give some disadvantages of friction.
- What are some ways to reduce friction?
- Solved Numerical of the exercise Ch 3 Physics Class 9.
- Find the momentum of body of mass 6km moving with a velocity of 25ms-1. What will be the velocity if the momentum becomes 200Ns?
- Find the momentum of body of mass 8km moving with a velocity of 30ms-1. What will be the velocity if the momentum becomes 300Ns?
- A body of mass 10kg is moving with velocity of 10ms-1. A force acts for 5 seconds reduce its velocity to 2ms-1. Find the momentum of body before and after application of force on it.
- A body of mass 8kg is moving with velocity of 12ms-1. A force acts for 6 seconds reduce its velocity to 3ms-1. Find the momentum of body before and after application of force on it.
- A force of 3400N is applied on a body of mass is 850km, find the acceleration produced by the force? How much force should be applied on a body of mass 425km to produce acceleration same as calculated.
- A force of 1400N is applied on a body of mass is 950km, find the acceleration produced by the force? How much force should be applied on a body of mass 325km to produce acceleration same as calculated.
- Find the mass of a body which is accelerated by applying a force of 200N, that speeds up to 3600ms-2. What should be the acceleration of the same body if the applied force changes to 280N.
- Find the mass of a body which is accelerated by applying a force of 300N, that speeds up to 40ms-1. What should be the acceleration of the same body if the applied force changes to 320N.
- An empty car has 1200km mess. Its engine can produce an acceleration of 4ms-2. If 300kg load is added to the mass by the passengers and luggage. What acceleration the same engine will produce?
- An empty car has 1400km mess. Its engine can produce an acceleration of 5ms-2. If 250kg load is added to the mass by the passengers and luggage. What acceleration the same engine will produce?
- A car is running on a circular part of highway having about 800m radius. The mass of car is 600kg and its velocity is 72 kmh-1. Find (i) Centripetal force exerted by the car. (ii) Centripetal acceleration of the car.
- A block is placed on a wet slippery floor. The mass of block is 15kg. When it is pulled through a string and spring balance, it shows force equal to 3N. Find the coefficient of friction.
- A block is placed on a wet slippery floor. The mass of block is 18kg. When it is pulled through a string and spring balance, it shows force equal to 4N. Find the coefficient of friction.