# Question 1

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

Solution:
(i) Moving a box placed on a table.

(ii) Pushing a carrom board coin.

# Question 2

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

Solution:
(i) Making a doll from china clay.

(ii) Stretching a rubber band.

# Question 5

In the following situations identify the agent exerting the force and the object on which it acts. State the effect of the force in each case.

(a) Squeezing a piece of lemon between the fingers to extract its juice.

(b) Taking out paste from a toothpaste tube.

(c) A load suspended from a spring while its other end is on a hook fixed to a wall.

(d) An athlete making a high jump to clear the bar at a certain height.

Solution:
 S. No Agent exerting the force Object on which it acts Form of effect (a) Fingers (a) Lemon as whole (b) Juice inside Change in shape Change in state of motion (b) Fingers (a) Tube as whole (b) Paste in side Change in shape Change in state of motion (c) Load (a) Spring Change in shape (d) Ground from which athlete takes jump (a) Athlete itself Change in state of motion

# Question 6

A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?

Solution:
The force brings about a change in the shape of hot iron piece.

# Question 7

An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?

Solution:
Electrostatic force.

# Question 8

Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.

Solution:
Force due to gravity. This does not bring a change in its state of motion because equal amount of force is being applied vertically upward. And they cancel one another.

# Question 9

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.

Solution:
The two forces acting on rocket are:

(i) Force due to gravity acting vertically downward.

(ii) Force of push acting upward.

# Question 10

When we press the bulb of a dropper with its nozzle kept in water, air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. What may be the reason for the rise of water in the dropper?

Solution:
The reason for the rise of water in the dropper is due to atmospheric pressure acting on water.