Q44. Why do we slip when we step on a banana peel?

 

Q45. Why the sole of our shoes is grooved?

 

Q46. Why do car wheels often spin on icy roads?

 

Q47. Why a pencil eraser loses tiny pieces of rubber each time we use it?

 

Q48. Why a vehicle slows down when brakes are applied?

 

Q49. Why it is convenient to pull the luggages fitted with rollers?

Or

Even a child can pull attaches and other pieces of luggage fitted with rollers. Why is it so?

 

Q50. What enables us to fix nails in a wall and knots to be tied?

 

Q51. What is a spring balance?

 

Q52. How does a bicycle stop when its brakes are applied?

 

Q53. When we strike a matchstick against the rough surface, it catches fire. Give reason.

 

Q54. Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.

 

Q55. How lubricants work?

 

Q56. Explain why the sliding friction is less than the static friction.

 

Last modified: Sunday, 8 September 2019, 3:32 PM