Trying to find Velocity and Kinetic Energy

AI Thread Summary
The discussion revolves around a physics problem involving a 4.0 kg mess kit that explodes into two parts, requiring the calculation of the original speed and the kinetic energy added by the explosion. Participants emphasize the importance of conservation of momentum rather than solely focusing on kinetic energy equations. The correct approach involves using the conservation of momentum to find the original velocity of the mess kit before the explosion. Additionally, the kinetic energy added can be calculated by comparing the total kinetic energy before and after the explosion. The conversation highlights the need to apply both momentum conservation and kinetic energy principles to solve the problem effectively.
Rhaen
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The problem is as follows:

A 4.0 kg mess kit sliding on a frictionless surface explodes
into two 2.0 kg parts, one moving at 3.0 m/s, due north, and
the other at 5.0 m/s, 30 degrees north of east. (a) What is
the original speed of the mess kit. (b) How much kinetic
energy was added to the mess kit by the explosion?

I don't know exactly how to get started with this though I know that there would not be any potential energy so we would have the equation:

K_1 = K_2
(1/2)m_1(V^2) = (1/2)m_2(V^2)

But because the explosion adds kinetic energy to the equation through a non-conservative force we would have the equation:

K_1 + W_nc = K_2
(1/2)m_1(V^2) + W_nc = (1/2)m_2(V^2)

Is this correct in my understanding and if so, where would I go from here to get the original velocity? Thank you very much for your time.

-Rhaen-
 
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Which quantity is conserved here?
 
Last edited:
It would be the left hand side that is conserved which would make:

(1/2)m_1(V^2) = (1/2)m_2(V^2) + W_nc

But what would I do after that if that is the correct equation?

-Rhaen-
 
I was thinking more of momentum.
 
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