Tiêu đề Class 09 Science Chapter 9 Force and Laws of Motion.pdf ✅

Force and Laws of Motion DPP-01 [Topic: Balanced and Unbalanced Forces, First Law of Motion, Inertia and Mass] Very Short Answer Type Questions 1. Can a force be measured in negative value and units. When? 2. What is the tendency of a body to resist its change of state called? 3. Which factor affects inertia? 4. When a carpet is beaten with a wooden stick, dust comes out of it. Explain. 5. Why is it advised to tie the luggage kept on the roof of a bus with a rope? 6. What is the SI unit of momentum? 7. Define 1 Newton. 8. Name the physical quantities whose units are: (i) kgms−2 (ii) kgms−1 9. Which of the following has more inertia: (a) a rubber ball and a stone of the same size. (b) a bicycle and a train? 10. A batsman hits a cricket ball which then rolls on a level ground. After covering a certain distance, the ball comes to rest. Why? (a) the batsman did not hit the ball hard enough. (b) velocity is proportional to the force exerted on the ball. (c) first law of motion. (d) there is no unbalanced force acting on the ball, so the ball would come to rest. [NCERT] 11. Why is it difficult to stop a truck suddenly than a motor bike? 12. A water tank filled up to two-thirds of its height is moving with water with a uniform speed. What will happen to the water in the tank on applying sudden brakes? 13. A ball is moving over a horizontal smooth surface with a constant velocity. What kind of forces are acting on the ball? 14. Which law of motion defines force? 15. Name the type of force which acts on the body when the resultant force is not equal to zero. 16. A passenger in a moving train tosses a coin which falls behind him. State the type of motion of the train. 17. What is the role of inertia? 18. While riding a bicycle if we stop paddling, why does the bicycle begin to slow down? [HOTS]

Force and Laws of Motion DPP-02 [Topic: Second Law of Motion] Very Short Answer Type Questions 1. What will be the momentum of a stone having the mass of 10kg when it is thrown with a velocity of 4ms−1 ? 2. Calculate the momentum of a bullet of 20g when it is fired from a gun with a velocity of 100m/s. 3. A ball of mass 150g moving with a velocity of 15ms−1 is brought to rest by a player in 0.1s. Calculate the force acting on the hands of the player. Short Answer Type Questions-I 4. The mass of a goods truck is 4000kg and mass of goods loaded is 2000kg. If the truck is moving with a velocity of 40km/hour, what will be its momentum? 5. An automobile vehicle has a mass of 1500kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7ms−2 ? 6. A force is applied on the object of 2kg on a frictionless surface. It produces an acceleration of 3ms−2. How much will be the force applied? 7. Which would require a greater force - accelerating a 2kg mass at 5ms−2 or a 4kg mass at 2ms−2 ? 8. Two similar trucks were moving with the same velocity on a road. One of them is loaded while the other is empty. Which of two will require larger force to stop? 9. Identify whether it is balanced or unbalanced force that causes the following different types of movements. (a) A person resting on an arm chair. (b) A cyclist braking. (c) A vehicle travelling at a constant speed on a straight road. (d) A car that that has a deceleration of 10ms−2. 10. A force of 5N produces an acceleration of 8ms−2 on mass mm1 and an acceleration of 24ms−2 on mass mm2. What acceleration will provide the same force if both the masses are tied together? 11. A motorcycle is moving with a velocity of 90km/hour and it take 5 seconds to stop after the brakes are applied. Calculate the force exerted by the brakes on the motorcycle if its mass along with the rider is 200kg. Short Answer Type Questions-II 12. A constant force acts on an object of mass 5kg for a duration of 2s. It increases the object's velocity from 3ms−1 to 7ms−1. Find the magnitude of the applied force. Now, if the same force was applied for a duration of 5s, what would be the final velocity of the object?