- #1
Planefreak
- 10
- 0
Homework Statement
A gun fires a round that goes 122 km in 170 seconds before impacting the ground. Ignore air resistance and the curvature of the earth. Find the muzzle velocity and angle.
Homework Equations
Vx = Vi(cos(theta)) Yx = Vi(sin(theta)) t= (-2Vy/-9.8) and D=(Vi2(sin(2theta)))/-9.8
The Attempt at a Solution
I found the correct muzzle velocity. Use distance 122*1000 then divide by time. This is horizontal velocity 717.647. Then use the third equation to find vertical. 170 = -2Vy/9.8.
Then use pythagorean to find final vector: 1099.502752
Now for the angle I used the fourth equation.
122000 = 1099.5027522(sin(2theta))/9.8
.9889931081 = sin(2theta)
40.74559192 degrees I guess this answer is wrong. I know the muzzle velocity is correct but according to the teacher it the angle is incorrect. Are my equations flawed or did I mess up?