Question

8. In a football match a ball is kicked by a
player with a force of 25N for 0.2 sec and
then by another player with a force of 70 N
for 0.1 sec in the same direction. If the foot
ball gains a velocity of 24 m/s after the two
kicks, the mass of the foot ball is nearly
1) 5kg
2) 10 kg
3) 2.5 kg 4) 0.5 kg​

Answer 1

The mass of the wall is equal to 0.5 kilogram.

Explanation:

Given,

• two different forces are applied one is applied for 0.2 second with a force of 25 Newton and the second is applied for 0.1secwith the force of 70 Newton.
• The final velocity is equal to 24 metre per second. therefore the change of velocity will also be equal to the final velocity is in the ball was initially at rest.

• Hence the mass of the ball is equal to, f1xt1 +f2xt2/ dv

= $\frac{25x0.2+70x0.1}{24}$

= 0.5kg

This is in accordance to the second law of Newton which states that the force is equal to the rate of change of linear velocity