- #1
jheld
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Homework Statement
A 20.0 ball is fired horizontally with initial speed Vi toward a 110 g ball that is hanging motionless from a 1.10 m -long string. The balls undergo a head-on, perfectly elastic collision, after which the 110 g ball swings out to a maximum angle theta = 50.0.
What was Vi?
Homework Equations
call ball mass .02 kg = A
call ball .11 kg = B
Avai + Bvbi = Avaf + Bvbf
Ki = Kf
(1/2)Avai^2 + (1/2)Bvbi^2 = (1/2)Avaf^2 + (1/2)Bvbf^2
vaf = (A - B)/(A + B) * vai
The Attempt at a Solution
vbi = 0 m/s
Bvbi = 0
Avai = -Avaf + Bvbf
vai = (A + B)/(A - B) * vaf
my problem is finding vaf, the final velocity of block A.
the final height y = L(1 - cos(theta)) = 1.1(1 - cos(50)) = .393 m