00:01
So in this question, you are giving two blocks, n -a -b, something like this, moving on a frictionless surface, and block a and b, a and b.
00:17
Now, these two blocks are held by a spring actually initially, and this spring is compressed by, initially by, i think, according to question, 45 meters.
00:33
45 centimeters.
00:35
So initially is compressed by delta air, which is 45 centimeters.
00:41
And it has a spring constant, which is k equals 600 and 55 newtembert meter.
00:49
So these two blocks initially moving at a speed, which is one, it will be not a meter per second.
00:58
And at some point, you just cut the spring, okay? you cut the spring, so, and you are asking to, when you cut it, when you cut it, the, so actually, sorry, there's a, yeah, there's a spring in between and there was a string and it had them together, right? then you cut the strain and the spring, they push them apart, right? and you ask you, what is the final speed of this blocks? let's, let's assume the final speed the blocks for a is v, a and that for b is vb, right? and then we can, we have a few, we can set up a few equations.
01:45
First, we notice that the total momentum must be conserved, right? initially, the total momentum is just, of course, m -a plus m -b times v -0, right, which is something you know.
02:00
So ma is massive a block and mb is massive block b, right? and this must be the final momentum.
02:09
So the final momentum, there is just m -a v -a times m -a -v -b -b, right? and secondly, we know that the total energy is we can save.
02:24
So the initial energy is just half m -a plus m -b -v -v -n -square.
02:31
Right.
02:32
And the final, i know there's also the kinetic energy, right? sorry, the not kinetic energy, the elastic energy store in the spring, that is half k, the spring constant times data air squared, right? and this must be the same, it must be the kinetic energy in the end, which is ma over 2 v .a squared plus mb over 2vb squared.
02:54
So you solve, you combine these two equations and solve them, then you should be able to get the two unknowns va and vp, i leave you to work out the equations, to solve this equation, which are just algebra equations and it should be easy to solve...