physical science
posted by junior .
A 6 kg bowling ball rolling at 5 m/s strikes a stationary 4 kg bowling ball. If ball #1 is moving forward at 2 m/s after the collision, what is the speed and direction of ball #2? What is the impulse of the system? If the collision last for .5 seconds, how much force is exerted?

Initial momentum = 6*5 = 30 kg m/s
Final momentum is therefore 30
30 = 6*2 + 4*v
4 v = 18
v = 4.5 m/s forward 
There is no change of momentum of the system so no impulse for the system.
However there is a change of momentum or impulse for Ball 2 of 18 kg m/s
Force = change of momentum or impulse / time
=18/.5 = 36 Newtons 
A cannon that is 10m long is designed to launch a 10kg ball over a castle wall.
In order to do this the ball must have a speed of at least 50m/s as it exits the
cannon. For every 10kg of explosives used, the force on the ball in the cannon
increases by 1000N. How many kg of explosives should they use?
2 Gravitation(100pts.)