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manenbu
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Homework Statement
Attached in the files, scan from Resnick and Halliday. Also the answers (notice that I use a different meaning for [tex]u[/tex], but it shouldn't matter.
Homework Equations
Conservation of momentum, and conservation of energy.
The Attempt at a Solution
Initial Energy of the system is [tex]mgh[/tex], initial momentum is 0.
I'll call the velocity of the wedge [tex]u[/tex] and the velocity of the block [tex]v[/tex].
The equations:
[tex]2mgh = mv^2 + Mu^2[/tex] - all potential energy goes to the velocities of both objects.
[tex]Mu = -mv \cos \alpha[/tex] - conservation of momentum - only the horizontal component of [tex]v[/tex] is taken into consideration.
I end up having this as an answer:
[tex]u = \sqrt{\frac{2gh}{M^2 + Mm \cos ^2 \alpha}}m \cos \alpha[/tex]
Which is, not correct according to the answer.
What did I do wrong?
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