- #1

Aerisk16

- 1

- 1

- Homework Statement
- work done in an collision which lasted for a very brief time interval

- Relevant Equations
- J=∆p=p_2-p_1=mv_2-mv_1

J=∑F∆t=F_ave ∆t=F_ave (t_2-t_1 )

W=Fs=∆K=K_2-K_1=1/2 mv_2-1/2 mv_1

Hello guys,

I need help on this problem,

"You throw a ball with a mass of 0.4kg against a brick wall. It hits the wall moving horizontally to the left at 30 m/s and rebounds horizontally to the right at 20m/s. (a) Find the Impulse of the net force on the ball during its collision with the wall (b) If the ball is in contact with the wall for 0.010s, find the average horizontal force that the wall exerts on the ball during the impact."

in the book, the answer for the Impulse is 20 N.s (there's a change in momentum) and the average force is 2000 N determine by dividing the Impulse 20 N.s by the time interval 0.01 s. Since there is change in velocity or speed, there is a change in kinetic energy and since the total work is equal to change in kinetic energy, I divided the change in kinetic energy which is -100 J by the average force 2000 N and get -0.05 m or 5 cm as displacement, I'm thinking this is a deformation of the ball. I'm having a doubt with my answer and also the size of the ball is not given...

I need help on this problem,

"You throw a ball with a mass of 0.4kg against a brick wall. It hits the wall moving horizontally to the left at 30 m/s and rebounds horizontally to the right at 20m/s. (a) Find the Impulse of the net force on the ball during its collision with the wall (b) If the ball is in contact with the wall for 0.010s, find the average horizontal force that the wall exerts on the ball during the impact."

in the book, the answer for the Impulse is 20 N.s (there's a change in momentum) and the average force is 2000 N determine by dividing the Impulse 20 N.s by the time interval 0.01 s. Since there is change in velocity or speed, there is a change in kinetic energy and since the total work is equal to change in kinetic energy, I divided the change in kinetic energy which is -100 J by the average force 2000 N and get -0.05 m or 5 cm as displacement, I'm thinking this is a deformation of the ball. I'm having a doubt with my answer and also the size of the ball is not given...