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phoebz
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Homework Statement
Two marble spheres of masses 30 and 20 grams, respectively, are suspended from the ceiling by massless strings. The lighter sphere is pulled aside, as shown in the diagram, through an angle of 75° and let go. It swings and collides elastically with the other sphere at the bottom of the swing.
a. To what maximum angle will the heavier sphere swing?
b. To what maximum angle will the lighter sphere swing?
-the length of the string is 95cm, see the diagram attached
Homework Equations
M=30g, V= speed of M, θ1 =angle of M
m=20g, v= speed of m, θ2 =angle of m
Law of conservation of kinetic energy:
1/2mv^2 + 1/2MV^2 = 1/2mv'^2 + 1/2MV'^2
Law of conservation of momentum:
x component: mv(cos75) =mv'(cosθ2) + MV'(cosθ1)
y component: mv(sin75) =mv'(sinθ2) + MV'(sinθ1)
The Attempt at a Solution
First I tried to find the velocity of m after it was released with the equation:
v =sqrt(2gLsinθ)
and got 4.24m/s
Then I plugged that into the law of conservation of KE and got:
1/2(20g)(4.24^2) = 1/2(20g)v^2 + 1/2(30)V^2
179.776 = 10v^2 + 15V^2
Then I plugged in the variables for the momentum equations:
x component: 20(4.24)(cos75) =20v'(cosθ2) + 30V'(cosθ1)
y component: 20(4.24)(sin75) =20v'(sinθ2) + 30V'(sinθ1)
I have tried all sorts of algebra to solve for the unknowns but keep getting complex equations that seem useless. Any help would be greatly appreciated!
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