(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

An arrow is shot vertically upward with an initial speed of 25 m/s. Two seconds later, another arrow is shot upward with the same speed. On its way up, the second arrow meets the first arrow on its way down. Assume that both arrows experience a constant downward acceleration of 9.8 m/s^{2}.

How long does it take (from the time the first arrow is shot) for the arrows to meet?

2. Relevant equations

d = vf * t - 0.5(a)(t)^{2}

t_{A1}= t_{A2}+ 2

3. The attempt at a solution

d_{A1}= 25t - 4.9t^{2}

d_{A2}= 25t - 4.9t^{2}

Since d_{A1}= d_{A2}

25t_{A1}- 4.9t_{A1}^{2}= 25t_{A2}- 4.9t_{A2}^{2}

Since t_{A1}= t_{A2}+ 2

25(t_{A2}+ 2) - 4.9(t_{A2}+ 2)^{2}= 25t_{A2}- 4.9t_{A2}^{2}

19.6t = 50-19.6

t = 1.55 s

The correct answer is 3.55 s

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Constant acceleration motion problem, please help!

**Physics Forums | Science Articles, Homework Help, Discussion**