# Homework Help: Vertical Displacement question

1. Sep 3, 2011

### CaYn

1. The problem statement, all variables and given/known data

Two basketball players are essentially equal in all respects. (They are the same height, they jump with the same initial velocity, etc.) In particular, by jumping they can raise their centers of mass the same vertical distance, H (called their "vertical leap"). The first player, Arabella, wishes to shoot over the second player, Boris, and for this she needs to be as high above Boris as possible. Arabella jumps at time , and Boris jumps later, at time tR (his reaction time). Assume that Arabella has not yet reached her maximum height when Boris jumps.

Find the vertical displacement , D(t)= hA(t)-hB(t)as a function of time for the interval o<t<tR , where hA(t) is the height of the raised hands of Arabella, while hB(t) is the height of the raised hands of Boris.
Express the vertical displacement in terms of H,g , and t.

2. Relevant equations
This is what I'm struggling with, I would use H(t) = v0t + 1/2at^2, but it says to answer in terms of their vertical leap, g, and t.

3. The attempt at a solution

I dont know where to begin if I have to use the given quantities.

2. Sep 3, 2011

### bjd40@hotmail.com

in yr eqn. a (acln.) should be replaced by (-g). t for ha eqn. is t and t for hb eqn. in t + tr. now subtract hb from ha. but this expression is true for t > tr. for 0<t<tr (that is the time interval when boris has not started his flight), D(t) = ha (as hb is zero for 0<t<tr). if this a text book problem have they given the answer?

3. Sep 3, 2011

### CaYn

It's a masteringphysics online, so no, they haven't given the answer.

I hate MP already xD

4. Sep 3, 2011

### CaYn

I figured it out, it was just MasteringPhysics being useless

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