Answer:
The law of conservation of momentum states that, in the absence of an external force, the momentum of a system remains unchanged.
Explanation:
The first question's answer is :
If, F=ma
Then, 15N= 2.1kg (a)
15/2.1=a
7.14=a
Therefore, acceleration = 7.14m/s^2
sorry I am not sure about the second question :-(
Einstein's equations showed that matter could be converted into energy; and vice-versa
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<span>In my opinion, I myself believe that there are only two supernovae. The first is the white dwarf. It makes sense because if something is too big for its size, it will "explode". Just like a basketball with too much air. Massive star supernovae is like something has reached it's full potential and cannot get any bigger or better.</span>
