Question

wah tap yat kijiye jo selisyas va fairanhaght me saman ho​

Answer 1

Answer:

NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of

Motion

Intext

Questions - 1 Page: 118

1. Which of the following has more inertia: (a) a rubber ball and a stone of the same

size? (b) a bicycle and a train? (c) a five-rupee coin and a one-rupee coin?

Solution

Since inertia is dependent on the mass of the object, the object with the greater mass will hold

greater inertia. The following objects hold greater inertia because of their mass.

(a) Stone

(b) Train

(c) Five-Rupee coin

2. In the following example, try to identify the number of times the velocity of the ball

changes: “A football player kicks a football to another player of his team who kicks the

football towards the goal. The goalkeeper of the opposite team collects the football and

kicks it towards a player of his own team”. Also identify the agent supplying the force in

each case.

Solution

Let the two football teams be team A and team B respectively. Initially, the football is at rest.

Now, the football is kicked by a player on team A to another player of team A. (The velocity of

the ball has changed 1 time so far). This change is brought on by the force applied by the

player who kicked the ball.

The football is now kicked by the other team A player towards the goal. (The velocity of the ball

has changed 2 times so far). This change is also brought on due to the force applied by the

team A player who kicked the ball.

The goalkeeper of team B stops the ball, bringing it to rest. (the velocity of the ball has

changed 3 times so far). This change is brought on by the force applied by the goalkeeper of

team B to stop the ball.

Finally, the goalkeeper of team B kicks the ball towards another player of team B. the velocity

of the ball changes for a final time, bringing the total count to 4. This change is also brought on