Question

9. Will force of friction come into play when rain water rolls down a glass window pane? Is it decreasing or increasing friction?
10. Joints in our body help in smooth movements due to cartilage. If cartilage tears it affects movements. How does friction play a role here?
11. Differentiate between static and sliding friction.
12. How do lubricants help to reduce friction?
13. The only friction which is a self adjusting force.
a. Sliding
b. Static
c. Fluid
d. Rolling
14. We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other. Give reason.
15. While travelling on a rickshaw, you might have experienced that if the seat cover is very smooth, you tend to slip when brakes are applied suddenly. Explain.
16. A box is placed on three different surfaces a marble floor(Fm), a cardboard sheet(Fc), and sand paper(Fs). The minimum forces required to simply move the box on the surfaces are (Fm), (Fc), (Fs) respectively. The three forces can be arranged in decreasing order as
a. (Fm), (Fc), (Fs)
b. (Fc), (Fs), (Fm)
c. (Fc), (Fm), (Fs)
d. (Fs), (Fc), (Fm)
17. In a cycling race, it is observed that a cyclist normally bends his body forward.(Figure below) The cyclist bends in order to

a. Feel comfortable
b. Reduce weight
c. Reduce the air drag
d. Increase energy consumption
18. Ram throws four stones having the same weight on four different surfaces icy, sandy, dry and cemented.He throws each stone with the same fore. On which of the given surfaces will the stone go the minimum distance before it stop?
a. Icy surface
b. Dry surface
c. Sandy surface
d. Cemented suface

Answer 1

Answer:

9 Yes

Explanation:

Answer 2

Answer:

a. (Fm), (Fc), (Fs) is the correct answer

Reduce the air drag is the correct answer

b. Dry surface is the correct answer