Question 1 :
Alida runs her toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be

Question 4 :
If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction?

Question 7 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0daf59b460d7261f376.PNG' /> From the above figure, if you tie a string around a brick and pull it by spring balance and then wrap a polythene on it and repeat the activity, will the spring balance measurement show any difference?

Question 8 :
Four children were asked to arrange forces due to rolling, static and sliding frictions in decreasing order. Their arrangements are given below. Choose the correct arrangement.

Question 9 :
If an object started moving, it would never stop if there were no friction.

Question 10 :
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 due to which of the following reasons?