a physics student drops a watermelon from the roof of the building. he hears the watermelon splat 2.50 seconds later. how high is the building? the speed of the sound is 340m/s. ignore air resistance.
Let's consider the following statement:
T = Tf + Ts,
where T is the total time elapsed from the moment of dropping the watermelon to the moment of hearing the splat (T = 2.5 s), Tf is the flight time of the lemon and Ts is the sound flight time. Let H be the height of a building. Then
H = g·Tf²/2 ==> Tf = √(2H/g)
Ts = H / Vs,
where Vs is the speed of the sound (Vs = 340 m/s).