Solving the Unequal Displacement of Balls Problem

[Lilly]

hi, if anyone knows how to do this question, could you please get me started?

A ball is thrown upward from the ground with an initial speed of 23.2 m/s; at the same instant, a ball is dropped from a building 16.1 m high. After how long will the balls be at the same height?
thanks...

 

[phoenixthoth]

Find a formula for the height of the first ball as a function of time. call this h_1(t).

Find a formula for the height of the second ball; call that h_2(t).

Then what can you do with the two height formulas to find out when the two balls are at the same height?

 

[Lilly]

thanks, i figured it out! :)

 

[phoenixthoth]

you're welcome.