# Is the ball's speed increasing?

1. Feb 19, 2015

### Westin

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

The figure below shows a moving ball, its momentum, and the net force acting on it an instant in time.

At this instant, the ball's speed is:

1) not changing

2) decreasing
3) increasing

2. Relevant equations

None.

3. The attempt at a solution

My guess would be that the balls speed is increasing since the force and change of momentum both go towards + x direction but I'm not totally sure, any help?

#### Attached Files:

• ###### Screen Shot 2015-02-20 at 12.43.27 AM.png
File size:
47.9 KB
Views:
64
2. Feb 20, 2015

### Orodruin

Staff Emeritus
Correct, but you could formalise your answer a bit. It is possible that the momentum and force both have positive components in the x direction and have decreasing speed. The real issue is about the angle between the force and momentum vectors.

3. Feb 20, 2015

### Westin

That makes sense, if the force was pointed straight down instead, would the ball's speed then be slowing down?

Last edited: Feb 20, 2015
4. Feb 20, 2015

### Orodruin

Staff Emeritus
Given the same momentum, yes.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted