# Projectile motion cannon help

1. May 9, 2006

### NIZBIT

Someone was fired 47 meters from a cannon. What is th einital muzzle velocity of the cannon?

Am I supposed to assume max range which puts the cannon at 45deg?

2. May 9, 2006

### daveb

If that's exactly how the question was worded, that would be my guess.

3. May 9, 2006

### NIZBIT

Well I took out the fancy stuff, but all they gave was the range.

4. May 10, 2006

### Hootenanny

Staff Emeritus
No angle? No mention of horizontal / vertical? Impact velocity etc?

~H

5. May 11, 2006

### siddharth

It's very easy to overlook useful information. So be careful. In fact, I think it's best if you post the question as it was given to you.

6. May 11, 2006

### nrqed

As Siddharth said, you should post the question exactly as it was given. Just stated the way you gave it, it is impossible to answer because there is no information about the initial angle. Sometimes useful information is given using words instead of numbers so every word counts.

7. May 11, 2006

### NIZBIT

OK you wanted it. Actually you don't need the angle and as stated earlier for max range the angle has to be 45.

In April 1959, Miss Victoria Zacchini was fired 47m from a cannon in Madison Square Garden, New York City. What was the inital muzzle velocity of the cannon?

$$max range=\frac {v^2}{g}$$

so

$$47=\frac {v^2}{9.81}$$

v=20.5 m/s

8. May 12, 2006

### arunbg

Of course , she was trying to set some kind of a record, and so the range would have to be maximum. See how useful posting the entire question can be ?

Arun