Question 1 :
If you place a book over 3 cylindrical pencils and push it, is it easier to move the book this way?
Question 3 :
Why the surface of mortar and pestle (silbatta) used for grinding is etched again after prolonged use?
Question 4 :
If you roll a pencil from an inclined plane, then cover the surface by cloth and roll the pencil again. In which case does it travel the least distance?
Question 5 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d072f59b460d7261f2f2.PNG' />
In the above image, two boys are shown applying force on a box. If the magnitude of the force applied by each is equal, will the box experience any force of friction?
Question 9 :
Imagine that an object is falling through a long straight glass tube held vertical; air has been removed completely from the tube. The object does not touch the walls of the tube. Will the object experience any force of friction?
Question 10 :
State true or false: There is a force of friction between the wheels of a moving train and iron rails.
Question 13 :
To sharpen the blade of a knife by rubbing it against a surface, which of the following will be most suitable?
Question 17 :
Will force of friction come into play when a rain drop rolls down a glass window pane?
Question 19 :
The frictional force on an object in a fluid depends on its ____ with respect to the fluid.
Question 20 :
Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor . Who will have to apply a larger force?
Question 21 :
To reduce friction, the shape of an aeroplane is made similar to which organism?
Question 22 :
A boy rolls a rubber ball on a wooden surface. The ball travels a short distance before coming to rest. To make the same ball travel longer distance before coming to rest, he may
Question 23 :
If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction?
Question 24 :
You spill a bucket of soapy water on a marble floor accicdentally . Would it make it easier or more difficult for you to walk on the floor?
Question 26 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d070f59b460d7261f2ef.PNG' />
In the above image, a boy is shown pushing the box from right to left.The force of friction will act on the box
Question 27 :
Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play
Question 28 : <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 29 :
State true or false: When the cutting edge of a knife is put against a fast rotating stone to sharpen it, sparks are seen to fly.
Question 30 :
Friction opposes the ___________ between the surfaces in contact with each other.
Question 34 :
You spill a bucket of soapy water on a marble floor accidentally. Would it make it easier or more difficult for you to walk on the floor?
Question 40 :
Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force?
Question 41 :
Which force comes into play when you push a book on a table?
Question 42 :
What happens to the strength of frictional force when logs are lifted by placing logs under it?
Question 45 :
You spill a bucket of soapy water on a marble floor accicdentally . Would it be dificult for you to walk on the floor ? Choose the correct reason of your answer.
Question 46 :
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?
Question 47 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d072f59b460d7261f2f1.PNG' />
In the above image, Two blocks of iron of different masses are kept on a cemented floor.Which one of them would require a larger force to move it from the rest position?
Question 48 :
When the cutting edge of a knife is put against a fast rotating stone to sharpen it, sparks are seen to fly due to which of the following reason(s)?
Question 49 :
Two boys are riding their bicycles on the same concrete road. One has new tyres on his bicycle while the other has tyres that are old and used. Which of them is more likely to skid while moving through a patch of the road which has lubricating oil spilled over it?
Question 50 :
A marble is allowed to roll down an inclined plane from a fixed height. At the foot of the inclined plane, it moves on a horizontal surface (a) covered with silk cloth (b) covered with a layer of sand and (c) covered with a glass sheet. On which surface will the marble move the shortest distance.
