# puck on ice.

276 views
Ice puck as the masses m1 = m2 and 0.5 kg = 0.3 kg, which are attached
on a spring having a coefficient of K1 = 40 N / cm and k2 = 15 N / cm.
1. puck moving towards each other with velocities v1 = 6 m / s and v2 = 4
m / s, and after the rebound of the drift from one another.
a) How much the speed pucks 1 and 2 at the moment when the spring is fully
collapsed?
b) To what extent at this time spring shrink?
c) What are the speed pucks after a rebound?

sorry for my bad English hope you  understand :)
asked Nov 17, 2014 in General

OK, try to make sense of the problem. So there are two masses that are not equal, correct? 0.5 and 0.3 kg respectively.

There are also two springs. How are these connected -- this is important as it determines the problem.

OK, based on the clarification below, we have a better idea of what this question is about.

a) When the springs are fully "collapsed", it means that both objects are pushed together the most. At this time, both have the same velocity. The next moment, they are going to move apart from each other. Then as this moment, it is equivalent to a total inelastic collision. So you have $P_{1i}+P_{2i}=P=(m_1+m_2)v$, which can lead you to find v.

b) For this part, you want to use energy conservation to find the compression of the spring. First find the difference of kinetic energy before and at the moment described in a). $\Delta E=K_{1i}+K_{2i}-\frac12 (m_1+m_2)v^2$.

Then $\Delta E=\frac12k_1x_1^2+\frac12k_2x_2^2$. You also need to consider that the forces between the springs are equal and opposite so $k_1x_1=k_2x_2$  -- for magnitudes only.

Solve these and you should have answer.

c) After rebound, the velocities of the blocks will follow the situation of an elastic collision and you can get it from there.
answered Nov 17, 2014 by (21,750 points)
m1=0,5 m2=0,3 :)

k1         k2
m1   O/\/\/\|   |/\/\/\O    m2
------>    <-------
v1            v2

i dont understand how it looks like when they are together