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navydrgn
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Homework Statement
A spring is attached to two blocks. The smaller block is 4.0 kg and the larger block is 8.0 kg. Initially the spring is in equilibrium and the blocks are separated by a d = 25 cm. The spring constant k = 400 N/m. No friction is present.
I now push on the two blocks compressing the spring. The separation between the two blocks is now 15 cm.
a) What is the speed of each block when they get back to being separated by 20 cm?
b) What will the maximum separation between the blocks be?
Homework Equations
Spring PE = .5*k*x^2
Kinetic Energy = .5*m*v^2
The Attempt at a Solution
So for a, I managed to solve for the potential energy of the system, with the spring compressed .1 meters.
PE = .5kx^2 -> .5 * 400 * (.1)^2 = 2 J.
Then I split that in half, and applied conservation of energy to solve for the kinetic energy at equilibrium for each block.
So for smaller block -> KE = .5*m*v^2 = 1, 1 = .5*4*v^2, 1/2 = v^2, v = .707 m/s or so.
Larger block 1 = .5 * 8*v^2, v = .5 m/sAnd part b, I assume the total stretch will be equal to the total compression, so stretch = 10 cm, thus the max separation should be 35 cm.
Are my answers correct?