# Homework Help: Projectile gun question

1. Oct 8, 2011

### euphoriax

1. The problem statement, all variables and given/known data
A gun fires a shell with a speed of 315m/s. Neglecting the effects of air resistance, calculate the maximum range of this gun

2. Relevant equations

t=(vf-vi)/a
v=d/t

3. The attempt at a solution
it doesn't give me an angle so I am kind of confused on how to solve this problem. I know that to solve this question, i need to figure out the angle the shell is fired at, then use the given velocity to find the x and y component velocities, find time using velocity and acceleration (the first equation), and then use that time to find the range of the gun by solving for d in the second equation. I don't think i have enough information?

2. Oct 8, 2011

### Staff: Mentor

You either:
1. Happen to have memorized the angle that gives a projectile its maximum range when fired over level ground;
2. Look up the optimal angle in your text or via the web.
3. Derive the formula for maximal angle from scratch.

Some options require more effort...