1. A passenger sitting in a car at next, pusher the car from within. The car doesn’t move, why?
2. Give the magnitude and directions of the net force acting on a rain drop falling with a constantspeed.
3. Why the passengers in a moving car are thrown outwards when it suddenly takes a turn?
4. What is the purpose of using shockers in a car?
5. Why are tyres made of rubber not of steel?
6. Wheels are made circular. Why?
7. A force is required to keep a body in uniform motion in a straight line. Comments.
8. On a rainy day skidding takes place along a curved path. Why?
9. Why does a gun recoils when a bullet is being fired?
10. Why is it difficult to catch a cricket ball than a tennis ball even whenboth are moving with the same velocity?
11. Calculate the impulse necessary to stop a 1500 kg car moving at a speed of 25ms–1.
( –37500 N–S)
12. Lubricants are used between the two parts of a machine. Why?
13. What provides the centripetal force to a car taking a turn on a level road?
14. What is inertial frame of reference?
15. An athlete runs a certain distance before taking a long jump. Why?
16. Action and reaction forces do not balance each other. Why?
17. The wheels of vehicles are provided with mudguards. Why?
18. China wares are wrapped in straw paper before packing?
20. Why is it difficult to walk on a sand?
21. The outer edge of a curved road is generally raised over the inner edge.
22. Explain why the water doesn’t fall even at the top of the circle when the bucket full of water is upside down rotating in a vertical circle?
23. Why does a speedy motor cyclist bends towards the centre of a circular
path while taking a turn on it?
24. If the net force acting upon the particle is zero show that its linear momentum remains constant?