Class 8th // Physics Short Answer type Questions Chapter - Force and Pressure

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Question 1. 
Give two examples of each of situations in which you push or pull to change the state of motion of objects.

Answer:-
(1) If a rubber ball or marble is placed on a very smooth surface and given a small push, it starts moving with some speed. If we keep an obstacle in the way of motion of the marble/ball, the marble/ball will stop moving at the obstacle. Here a push is given to the marble/ball at rest to change its state of rest to motion.

(2) If a child is placed on a hanging swing in the state of rest and the swing is pulled again and again by a rope, the swing will move to and fro with a speed. If the pull is bigger, the swing will move at a bigger distance. This is an example of a pull that changed the state of an object from the rest of the motion.

Question 2.
Give two examples of situations in which applied force causes a change in the shape of an object.

Answer:-

1. If an inflated balloon is taken and pressed from two sides with a hand, its shape changed, i.e., the figure is disturbed. If the inflated balloon is pressed with more force, the balloon will burst.
2. If a plate of steel is beaten with a hammer, after four-five big blows the plate’s shape will change.
   
   Question 3.
   A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?
   
   Answer.
   The shape of the hot piece of iron changes. It flattens and becomes thinner than earlier. This is the effect of force due to hammering the piece of iron.
   
   

   Question 4.
   A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.
   
   Answer.
   The two forces that are acting on the rocket immediately after leaving the launching pad are:

   1. Force of gravity of earth acting down-ward
   2. The frictional force produced by air particles.
      
      Question 5.
      Fill in the blanks in the following statements:
   1. To draw water from a well, we have to ……….. at the rope.
   2. A charged body………….an uncharged body towards it.
   3. To move a loaded trolley, we have to…………...it.
   4. The north pole of a magnet…………….the north pole of another magnet.

   Answer:-

   1. pull
   2. attracts
   3. pull/push
   4. repels.