Question

a rock dropped from a high platform is moving at 24 m/s downward when it strikes the ground. Ignore air resistance. How fast was the rock moving when it had fallen only one-fourth of the distance to the ground?

8.0 m/s , 6.0 m/s, 18.0 m/s , or 12.0 m/s

? :/

Answer 1

please wait a moment, since I have to draw a table

Answer 2

ok!

Answer 3

I'm pondering....

Answer 4

ok! :)

Answer 5

we have the subsequent situation:

so total mechanical energy is:
\[{E_{TOTAL}} = \frac{1}{2}m{v^2}\]
where m is the mass of the ball or the mass of the rock