NCERT Solutions Curiosity Chapter 5 .2 What Can a Force Do … · 5.3 Are Forces an Interaction Between Two or More Objects? — In-text Questions
Book page 655 Updated on2026-09-05
Q1.
What effect can the application of force have on objects?
Answer
The force applied on an object may
make an object move from rest — a football lying still starts moving when it is kicked;
change the speed of an object if it is moving — brakes slow a cycle down, pedalling speeds it up;
change the direction of motion of an object — a bat turns a moving ball back;
bring about a change in the shape of an object — a balloon flattens when pressed, dough spreads under a belan;
cause some or all of these effects at once — a fielder's hands both slow a ball and turn it aside.
Q2.
Does this mean that whenever there is a change in speed or direction, or change in shape, a force is acting on the object?
Answer
Yes — none of these take place without the action of a force.
So if you see a moving object speed up, slow down, stop, turn, or get squeezed or stretched, you can say with certainty that some force is acting on it, even if you cannot see what is applying it. The rolling ball that stops on its own is the standard example: something must be acting on it, and in the next section we find that it is friction.
Careful: the statement does not work backwards. If nothing is changing, it does not follow that no force acts — the forces on the object may simply be balancing one another (see the A step further box on the same page).
Q3.
Think of all the actions listed in Table 5.1. How many objects are involved in each of the actions? Do you notice that forces result only when two objects are interacting in some way or the other?
Answer
At least two objects are involved in every single action, and yes — a force appears only when two objects interact.
Action from Table 5.1
Object applying the force
Object on which it acts
Friend holding your moving bicycle to stop it
Your friend's hands
The bicycle
Hitting a moving ball with a bat
The bat
The ball
Pressing an inflated balloon
Your fingers
The balloon
Opening a drawer
Your hand
The drawer
Why it happens: a force is not something an object has by itself; it is what one object does to another. That is why the definition is written as — a force is a push or pull on an object resulting from the object's interaction with another object. Remove one of the two objects and the force disappears.