Homework Help: Cannonball conceptual question

1. Apr 8, 2013

freshcoast

1. Problem statement
Immediately after being fired from a cannon, a high speed cannonball does not posses..

a) mass
b) force
c) momentum
d) kinetic energy
e) but, it has all these qualities while moving!

2. Related equations

3. Attempt at solution
I'm thinking the cannon ball does not possess momentum since there are external forces acting upon the object and if we are just looking at the ball by itself, it is not part of a 2-part system which is needed to have momentum.

Or if that's wrong I think it must have all the qualities because the ball has mass, force came from the cannon thus giving it momentum and it also possesses kinetic energy since the object is moving

2. Apr 8, 2013

voko

What IS momentum?

And what force acts on the canonball after it has left the barrel?

3. Apr 8, 2013

freshcoast

Momentum occurs when a 2-part system's internal forces act upon each other or collide

And the external forces that are acting on the ball after it leaves the cannon would be gravity

4. Apr 8, 2013

arildno

Really?
What does your textbook define momentum to be?

5. Apr 8, 2013

freshcoast

momentum is by Google definition, the quantity of motion of a moving body , measured as a product of its mass and velocity

So does that mean anything that is moving has momentum? Isn't it possible to not have momentum but have kinetic energy?

6. Apr 8, 2013

arildno

"So does that mean anything that is moving has momentum"
Yes.
"Isn't it possible to not have momentum but have kinetic energy?"
No.

7. Apr 8, 2013

voko

What about the air? Does it act on the ball in any way?

8. Apr 8, 2013

freshcoast

Air resistance would be a force acting the opposite direction of the cannonball and would cause it to slow down