physics
posted by Soly on .
Will check my work and help me with the last two problems please?
A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?
(12 kg/m/s) / 4kg=3m/s
A ball is moving at 4 m/s and has a momentum of 48 kg m/s. What is the ball's mass?
(48kg/m/s) / (4m/s) =12 kg
A 1kg chunk of putty moving at 1 m/s collides with and sticks to a 5kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of? (This one I don't know how to work)
A 1000kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is? (This one I don't know how to work)

on the fourth: comentum is conserved, final momentum is = initial momentum.
on the last:
vf^2=vi^2+force*distance
where distance is average velocity*time or
(vf+vi)/2 * t
solve for force
first two correct.