Question 1 :
Will force of friction come into play when a rain drop rolls down a glass window pane?
Question 2 :
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 farthest distance?
Question 5 :
Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play
Question 6 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0d9f59b460d7261f375.PNG' />
From the above figure, if you tie a string around a brick and pull it by spring balance, what will the spring balance measure?
Question 7 :
In science, the common name of gases and liquids is _______.
Question 9 :
State true or false: There is a force of friction between the wheels of a moving train and iron rails.
Question 10 :
Can you hold a glass or write on the board with a chalk without any friction?
Question 11 :
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.
Question 14 :
The frictional force on an object in a fluid depends on its ____ with respect to the fluid.
Question 16 :
What happens to the strength of frictional force when logs are lifted by placing logs under it?
Question 17 :
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 18 :
Cartilage is present in the joints of our body, which helps in their smooth movement. With advancing age, this cartilage wears off. How would this affect the movement of joints?
Question 20 :
Alida runs her toy car on a 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 21 :
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 23 :
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 24 :
Does the distance covered depend on the nature of the inclined surface on which the object rolls over?
Question 25 :
A toy car released with the same initial speed will travel farthest on
Question 26 :
In fact, when a machine is operated, heat generated causes much wastage of _________.
Question 27 :
It is obvious that the force of friction will ______ if the two surfaces are pressed harder.
Question 29 :
<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 30 :
Friction opposes the ___________ between the surfaces in contact with each other.