a rocket of total mass m is traveling at a speed v. the engine of the rocket is fired and fuel is used up. the mass of the rocket decreases to M/2 and its speed increases to 2v.
what happens to the kinetic energy of rocket
a it doubles
b it halves
c it increases by a factor of four
d it stays the same
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Answer:
a) it doubles
Explanation:
By substituting M and v with simple numbers, you can get the initial KE and the final KE and work it out from there.
Let's say M=2kg and V=4m/s
KE= 1/2mv^2
initial KE= 1/2(2)(4)^2 = 16J
final KE= 1/2(2/2)2(4)^2 = 32J
32J/16J = 2
therefore, it doubles.
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