Angle of a trajectory required to make it go a specified distance?

[dimmermanj]

Here is the problem at hand:

A gun has a muzzle speed of 100 meters per second. What angle of elevation should be used to hit an object 180 meters away? Neglect air resistance and use g = 9.8 m / sec^2 as the acceleration of gravity.


I attempted to solve this by calculating the time required for the ball to travel the distance and then correlating that with the height to equal zero at that time..but honestly I'm just plain lost on this one, so any help would be great!

Jim

 

[Integral]

If you show us what you have done, we can help find the errors. No effort, no help.