# Maximum Range

1. Feb 12, 2010

### huybinhs

1. The problem statement, all variables and given/known data

On level ground, what is the maximum range (in m) of a cannon with muzzle speed 322 m/s?

Please take a look at this:

http://i995.photobucket.com/albums/af79/huybinhs/cannon2.gif

2. Relevant equations

R = (V0^2 * sin2angles)/g

3. The attempt at a solution

I think (not sure) the angles in the pic is 30 degree. And came up with the answer:

Thanks so much!

2. Feb 12, 2010

### Gib Z

Umm...unless you were meant to get a protractor and measure the angle, you don't have enough information for the problem. Also, the "direction" of the range is to the right. Were you given ANY other information?

3. Feb 12, 2010

### Jebus_Chris

If an object is launched on a flat surface the maximum range comes when the angle is 45.

4. Feb 12, 2010

### Keldon7

Take another look at your range formula, you're given velocity and you know it's proportional to the sine of 2*angle. For what angle is sine 2*angle a maximum?

5. Feb 12, 2010

### huybinhs

Again:

http://i995.photobucket.com/albums/af79/huybinhs/cannon2.gif

6. Feb 12, 2010

### huybinhs

So you mean after looking at the pic link, and you think the angle is 45 degree????

7. Feb 12, 2010

### Jebus_Chris

Does it look like the picture is drawn to scale?

8. Feb 12, 2010

### Keldon7

In all fairness, even if it was scaled up the angle would remain identical, similar triangles and such. But, I don't think they're putting emphasis on the picture here, the question is simply "What is the maximum range for a cannon with muzzle velocity 322m/s?". So Jebus_Chris is right.

9. Feb 13, 2010

### huybinhs

10. Feb 13, 2010

### Jebus_Chris

If an object is launched on a flat surface the maximum range comes when the angle is 45.

11. Feb 13, 2010

### huybinhs

So It comes out with:

R = (V0^2 * sin2angles)/g

=> R = 10580 m. Is this correct?

12. Feb 13, 2010

### huybinhs

I got it right. Thanks so much for your help ;) Please help me to complete the "Calculate the time it took the marble to travel from N to P" problem ;)