Question

a man throws a ball of mass 150 g to a wall with a velocity of 20m/s and it rebounces with the same velocity. Find the change in the momentum.​

Answer 1

Answer :-

Change in momentum of the ball is -6 kg m/s .

Explanation :-

We have :-

→ Mass of the ball (m) = 150 g = 0.15 kg

→ Initial velocity (u) = 20 m/s

→ The ball rebounces with same velocity.

To find :-

→ Change in momentum .

________________________________

Initially the ball was moving in a certain direction. After hitting the wall, the ball rebounces in the opposite direction. So, final velocity of the ball (v) will be -20 m/s .

Initial momentum of the ball :-

= Mass × Initial velocity

= m × u

= 0.15 × 20

= 3 kg m/s

Final momentum of the ball :-

= Mass × Final velocity

= m × v

= 0.15 × (-20)

= -3 kg m/s

Change in momentum :-

= Final momentum - Initial momentum

= (-3 - 3) kg m/s

= -6 kg m/s

Answer 2

Answer:

Question :-

• A man throws a ball of mass 150g to a wall with a velocity of 20m/s and it rebounces with a same velocity. Find the change in the momentum.

$\sf\tt\large{\purple {\underline {\underline{⚘\;Answer:}}}}$

$\sf\tt\large{\blue {\underline {\underline{⚘\;The \;change \;in \;momentum \;of \;the \;ball \;is \;-6kgm/s:}}}}$

$\sf\tt\large{\red {\underline {\underline{⚘\;Given:}}}}$

• A man throws a ball of mass 150g to a wall with a velocity of 20m/s and it rebounces with a same velocity.
• Mass of the given ball=150g=0.15kg.

$\sf\tt\large{\red {\underline {\underline{⚘\;To find:}}}}$

• Change in momentum of the given ball.

$\sf\tt\large{\red {\underline {\underline{⚘\;Solution:}}}}$

• Here,

• First we should find the initial momentum and final momentum of the given ball then at final lets find the change in momentum of the given ball.

$\sf\tt\large{\red {\underline {\underline{⚘\;Case (i):}}}}$

• Initial momentum =mass ×given initial velocity.

• Lets apply the values,

• Initial momentum =0.15kg×20
• Initial momentum =3 kg m/s.

$\sf\tt\large{\red {\underline {\underline{⚘\;Case (ii):}}}}$

• Final momentum =mass×final velocity of ball

• Lets apply the values we get that,

• Final momentum =0.15kg×(-20)m/s
• Final momentum =-3kg m/s.

$\sf\tt\large{\red {\underline {\underline{⚘\;Final \;result:}}}}$

• Change in momentum of the given ball =Final momentum- initial momentum
• Change in momentum of the given ball = -3 - 3

• Change in momentum of the given ball =-6kg m/s.