Momentum (Cannon fires at angle & recoils)

1. Oct 10, 2008

CaptainSFS

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

A circus cannon, which has a mass M = 5000 kg, is tilted at q = 40°. When it shoots a projectile at v0 = 80 m/s with respect to the cannon, the cannon recoils along a horizontal track at vcannon = 1 m/s with respect to the ground.

1. At what angle to the horizontal does the projectile move with respect to the ground?

2. Relevant equations

3. The attempt at a solution

In order to solve this first question, I first found the horizontal velocity of the ball. 80cos(40) gives me about 61.xxx m/s. The cannon recoils in the opposite direction, so I add 1 m/s. I then use arccos(62.xxx/80) to find the new angle with respect to the ground. This is not the correct answer. I'm not sure what to do.

2. Oct 10, 2008

Rake-MC

An interesting question, according to the diagram, they want you to solve for $$\theta$$

Right?

Then please label the 40 degrees.

3. Oct 10, 2008

CaptainSFS

what do you mean "Then please label the 40 degrees"?

If you're implying that the answer is 40 degrees, I can assure with certainty that it isn't. I input these values into my homework online, and it returns with either an "OK" or "NO". I've tried 40 degrees, that was my first guess. =/

So, there's something else going on in the problem that I'm not understanding.

4. Oct 10, 2008

Rake-MC

The question is asking you to solve for theta in the diagram. Is this correct or not?

If this is correct. Then where is the 40 degrees in the diagram and what does it represent.
Your description states that q = 40 degrees. However q is not mentioned anywhere before or after that statement. What is q?

5. Oct 10, 2008

CaptainSFS

q is typically the letter they use to denote theta, since I cannot input a theta symbol into my answer field.