Answer:

Explanation:
If the collision is elastic and exactly head-on, then we can use the law of momentum conservation for the motion of the 2 balls
Before the collision

After the collision

So using the law of momentum conservation


We can solve for the speed of ball 1 post collision in terms of others:

Their kinetic energy is also conserved before and after collision


From here we can plug in 






Answer:
leverage
Explanation:
Leverage ...this allows you to use less force through a longer distance
Incandescent lights get hot very quickly and therefore can easily burn u or catch fire
I am going to need a picture for this question