CBSE Important Questions

Q . 1. Define SI unit of force.(1)

Q . 2. A body is moving with a uniform speed of 15 m/s on a circular track. Why is its motion called acceleration motion.(1)

Q . 3. What is the distance travelled and displacement of a body as its moves from A to B via C.(2)

Q . 4. A motor boat starting from rest on a lake accelerates in a straight line at a constant rate of 2m/s2 for 4 seconds. How far does the boat travels during this time.(2)

Q . 5. Name the force which keeps various planets in their orbits. Write down the formula for the force which exists between two bodies of mass m1 and m2 separated by a distance R from each other.(2)

Q . 6. State Newton’s second law of motion. A ball is thrown on a smooth surface with a force and it stops after some time. Is it supporting First law of motion. Give reasons for your answers.(2)

Q . 7. Velocity-time graph of a body is given above. Answer the following questions (3)

1. Which part of the graph shows uniform acceleration.
2. Which part of the graph shows uniform retardation.
3. Calculate the total distance travelled by the body.
4. Which part of the graph shows zero acceleration.(3)

Q . 8.

1. Derive the first equation of motion v=u + at graphically.
2. Write the equation describing the principle of conservation of momentum.
3. Why does the Gun recoil when a bullet is fired from it. (5)