Posted by Michael on Sunday, April 12, 2009 at 11:36pm.
A rubber ball is thrown against the wall. The ball has a mass of 4 g and strikes the wall perpendicularly with a speed of 12 m/s. The acceleration is constant while the ball is touching the wall. After touching the wall, the center of mass moves .5 cm toward the wall, and back out from the wall.
what is the magnitude of the time average force?
>>First I found the impulse delivered by the wall which is Px'Px (momentum) = .096 N/s. Then I tried to find the change in time by taking (.5*2*(1/1000))/12. For this change in time i got 8.33E4. However, the answer .096/8.33E4 was incorrect. Help!

Physics  drwls, Sunday, April 12, 2009 at 11:55pm
The average velocity from first impact to turnaround (maximum compression) is 6 m/s. The time required to reach maximum compression (at constant acceleration) is T = 0.5 cm/(600 cm/s)= 8.3*10^4 s. Acceleration is
a = (delta V)/T
a = (12 m/s)/(8.3*10^4s) = 14,400 m/s^2
M = m a = (0.004 kg)(14,400 m/s^2) = 57.6 N
I understand how you got the impulse. The units of momentum are not N/s. The time agrees with mine, but mine is half the total interval of contact, and yours is the total time of contact. Something is wrong there
Answer This Question
Related Questions
 Physics  A tennis ball with a velocity of 24.4 m/s is thrown perpendicularly at...
 physics   A tennis ball with a speed of 11.4 m/s is thrown perpendicularly at a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 8.64 m/s. If the ball is in contact with the wall for 0.0104 s, what is the average magnitude of acceleration of the ball while it is in contact with the wall?
 Physics  A tennis ball with a speed of 5.0 m/s is thrown perpendicularly at a ...
 physics  I have been stuck on this for a while now and cant figure out what it ...
 physics  A tennis ball with a speed of 6.0 m/s is thrown perpendicularly at a ...
 physics  A tennis ball with a velocity of +9.6 m/s to the right is thrown ...
 Physics  A girl of mass 55 kg throws a ball of mass 0.8 kg against a wall. The ...
 physics  A girl of mass 60 kg throws a ball of mass 0.8 kg against a wall. The...
 Physics URGENT  A tennis ball with a velocity of +10.7m/s to the right is ...
 physics  A tennis ball with a speed of 12.5 m/s is moving perpendicular to a ...
More Related Questions