A ball with a mass of #15 kg# moving at #6 m/s# hits a still ball with a mass of #21 kg#. If the first ball stops moving, how fast is the second ball moving? How much kinetic energy was lost as heat in the collision?
1 Answer
Explanation:
Conservation of momentum states that before and after a physical reaction there must always be the same amount of momentum.
Momentum is the product of mass and velocity, or
where
Before the reaction, there is a total momentum of
because the question describes the
After the reaction, we know that the
Therefore, after the reaction,
The answer is rounded to the first decimal place.
For the second part of the question, kinetic energy is given by the formula
where
Before the reaction, total kinetic energy would therefore be
After the reaction, we would have
The change in kinetic energy is
Feel free to check my working, there's some room for error-carried-forward due to rounding. Hope it's somewhat clear.