Q9. Assertion (A): A cricket fielder pulls his hands backwards while catching a fast ball. Reason (R):...

Q9. Assertion (A): A cricket fielder pulls his hands backwards while catching a fast ball. Reason (R): Increasing the time taken to stop the ball reduces the force on the hands.
Q10. Assertion (A): The action and reaction forces do not cancel each other. Reason (R): The action and reaction forces act on two different objects.
Q11. What are balanced forces? Give one example from daily life. [2]
Q12. State Newton's first law of motion. Why does a person sitting in a car fall backwards when the car suddenly starts? [2]
Q13. Why is it easier to walk on a rough floor than on a wet, polished floor? [2]
Q14. A weightlifter holds a barbell of total mass 30 kg steady. Calculate the force she applies on it. (Take g = 10 m s^-2) [2]
Q15. A gun recoils when a bullet is fired from it. Name the law that explains this and state it. [2]
Q16. A constant force of 20 N acts on a 4 kg block initially at rest on a frictionless horizontal surface. Calculate (i) the acceleration of the block and (ii) the distance it travels in 3 s. [3]
Q17. Two forces of 12 N and 5 N act on a 2 kg block. Find the magnitude of the net force and the acceleration of the block when the forces act (i) in the same direction and (ii) in opposite directions. [3]
Q18. Explain, using Newton's second law, why an airbag in a car reduces the risk of injury to a passenger during a sudden stop. [3]