Class 9 Physics | Force & Laws of Motion | Exercise l Numericals
Examples : • "Class 9 Physics | Force & Laws of Motion ... In this video, we solve NCERT Class 9 Science Chapter 8: Force and Laws of Motion exercise numericals step by step in a very simple and easy-to-understand manner. 🚀 👉 What you’ll learn in this video: ✔️ Detailed explanation of Newton’s Laws of Motion ✔️ Step-by-step solutions to NCERT exercise problems ✔️ Important formulas and tricks to solve numerical questions ✔️ Concept clarity with examples from daily life This video is perfect for Class 9 CBSE students preparing for exams, as well as for quick revision before tests. ✨ 📘 Chapter: Force and Laws of Motion (Class 9 Science) 📖 Source: NCERT Solutions | CBSE Syllabus If you find this video helpful, don’t forget to LIKE 👍, SHARE 🔁, and SUBSCRIBE 🔔 for more Class 9 Science lessons! 5. A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 tonnes (Hint: 1 tonne = 1000 kg.) 6. A stone of 1 kg is thrown with a velocity of 20 m s–1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice? 7. A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate: (a) the net accelerating force and (b) the acceleration of the train. 8. An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 m s–2? 12. A hockey ball of mass 200 g travelling at 10 m s–1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s–1. Calculate the magnitude of change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick. 13. A bullet of mass 10 g travelling horizontally with a velocity of 150 m s–1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also calculate the magnitude of the force exerted by the wooden block on the bullet. 14. An object of mass 1 kg travelling in a straight line with a velocity of 10 m s–1 collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object. 15. An object of mass 100 kg is accelerated uniformly from a velocity of 5 m s–1 to 8 m s–1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object. 17. How much momentum will a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80 cm? Take tts downward acceleration to be 10 m s–2.
