Question

19.
How can we increase friction?
a) By applying extra force
b) By using ball bearings
c) By reducing contact area between the surs
d) By making surface rough
20.
We must oil our bicycles regularly to
a) reduce wear and tear of the bicyde
b) To make the bicycle tyres slippery
c) to give it a shiny look
d) to keep the bicycle clean​

Answer 1

1.D

2.A

Here is ur answer my friend

Answer 2

Answer:

(19) D

(20) A

Explanation:

..........