Posted by **Katie** on Monday, February 27, 2012 at 1:33pm.

A 220-g ball strikes a wall with a speed of 7.0 m/s and rebounds with only 37% of its kinetic energy. What is the speed of the ball immediately after rebounding?

What is the magnitude of the impulse of the ball on the wall?

If the ball was in contact with the wall for 9.9 ms, what is the magnitude of the average force exerted by the wall on the ball during this time interval?

- physics -
**Elena**, Monday, February 27, 2012 at 5:33pm
KE2=0.37KE1

(m(v2)^2)/2=0.37(m(v1)^2)/2.

The speed of the ball immediately after rebounding is

v2=v1(sqroot(0.37)) =0.6•7=4.2 m/s.

The magnitude of the impulse of the ball on the wall:

delta(p) = p2 - p1= mv2 - (- mv1) = mv2 + mv1=

m(v2+ v1) = 0.22•(4.2 + 7) = 2.464 kg•m/s.

The magnitude of the average force

exerted by the wall on the ball during this time interval:

F•delta(t) = delta(p),

F= delta(p)/ delta(t) = 2.464/9.9=0.249 N.

- physics -
**Katie**, Tuesday, February 28, 2012 at 10:19am
Thanks. the impulse is correct but the magnitude of the average force is not.

## Answer This Question

## Related Questions

- Physics - A 0.3 kg ball strikes a wall head on and then rebounds straight back. ...
- physics - A 0.060-kg handball is thrown straight toward a wall with a speed of 9...
- physics-impulse - A tennis ball of mass m = 0.068kg and speed v = 21m/s strikes ...
- Physics - A tennis ball of mass= 0.058 kg and speed= 19 m/s strikes a wall at a ...
- PHYSICS PLEASE HELP!! - A tennis ball of mass= 0.058 kg and speed= 19 m/s ...
- Physics - An astronaut throws a ball with mass m to the right with speed v. It ...
- Physics - an astronaut throws a ball with mass m to the right with speed v. It ...
- physics - A ball of mass m strikes a wall that is perpendicular to its path at ...
- physics for scientists and engeneers I - A tennis ball of mass m = 0.065 kg and ...
- Physics - A 275-gram ball bounces off a wall. The ball stays in a horizontal ...

More Related Questions