Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 6.82 m. The stones are thrown with the same speed of 8.88 m/s. Find the location (above the base of the cliff) of the point where the stones cross paths.

I can't figure out how to manipulate free fall...please help!!!

1 answer

the height of the falling stone is

6.82-8.8t-4.9t^2

the height of the stone thrown upward is

8.8t - 4.9t^2

So, when do they meet? At t=0.3875

Now plug that into either function to get the height at that time.

http://www.wolframalpha.com/input/?i=solve+6.82-8.8t-4.9t^2++%3D++8.8t+-+4.9t^2