A ball is thrown vertically upward with initial velocity v. Find the maximum height H of the ball as a function of v. Then find the initial velocity v required to achieve a height of H.

Question

anonymous · Answer

for the first part, what forces are acting upon the ball?  only the initial velocity V or something else?

anonymous · Answer

So:
vf^2 = vi^2 + 2ad
At the top, final velocity is 0, so
0 = vi^2 + 2ad
We know that the only acceleration is that of gravity, and that vi is just what you call "v"
0 = v^2 + 2(-9.8)(d)
19.6d = v^2
d = v^2    /    19.6

There you go!

anonymous · Answer

thats all the question says...its more a theoretically question... ive tried answering it a couples of ways (since our electronic submission allows for multiple entry)..

anonymous · Answer

i have tried v^2/19.6 and it says that is incorrect

anonymous · Answer

Is it asking you for a number or a formula?

anonymous · Answer

Height H achieved with given initial velocity v:
Initial velocity v required to achieve given height H:

anonymous · Answer

im not sure...because it wont let me introduce another variable such as g ...says that is incorrect

anonymous · Answer

here is what I have, your height H is going to equal the initial velocity V - the force of gravity, which is mass times acceleration.  H=V-ma

anonymous · Answer

it says that ma is not defined in this context unfortunately

anonymous · Answer

i am sorry, i dont quite know what its asking

anonymous · Answer

thats ok, thanks for trying to help though