Physics 5 ball graph: Follow the motion of the balls and consider the direction of the forces...

[Amelinator]

This graph is confusing. I've tried all of the obvious answers. I just don't understand.

 

[Amelinator]

So....
None: Yellow Ball
Left: Blue Ball
Left: Black Ball
None: Green Ball
Right: Red Ball
This is the correct answer; I guessed and got it right, but why is the blue ball only left when it first goes right and then left? shouldn't it be both?

 

[lev888]

View attachment 37126
This graph is confusing. I've tried all of the obvious answers. I just don't understand.

This is an animation, not a graph.

 

[The Highlander]

So....
None: Yellow Ball
Left: Blue Ball
Left: Black Ball
None: Green Ball
Right: Red Ball
This is the correct answer; I guessed and got it right, but why is the blue ball only left when it first goes right and then left? shouldn't it be both?

Why do you think the blue ball is experiencing forces in two directions?

Compare its history (the grey circles?) to that of the black ball; it looks very similar except that the distances between each of the grey circles is greater (and there are fewer of them)... implying what?

Hope that helps.

 

[Dr.Peterson]

So....
None: Yellow Ball
Left: Blue Ball
Left: Black Ball
None: Green Ball
Right: Red Ball
This is the correct answer; I guessed and got it right, but why is the blue ball only left when it first goes right and then left? shouldn't it be both?

As I understand it, the black ball starts at the right and moves left, accelerating, while the blue ball starts and ends at the left, moving to the right and back.

Imagine the whole picture turned on its side. If you toss the blue ball in the air, it will go up, then down. Did the force change? No, the force of gravity is always downward, but at first it is opposing the motion, making it slow down, and then it is with the motion, making it speed up. At all times the ball is accelerating downward, meaning that its velocity is becoming more negative.

 

[The Highlander]

So....
None: Yellow Ball
Left: Blue Ball
Left: Black Ball
None: Green Ball
Right: Red Ball
This is the correct answer; I guessed and got it right, but why is the blue ball only left when it first goes right and then left? shouldn't it be both?

I have only just noticed this post (where you show the correct answers). My post above was in response only to your original post (where your answer for the blue ball was incorrect).

I was going to say that it's difficult to offer any explanation for your confusion because we cannot see the animation that you see (and, therefore, are at a loss to know what may be causing your confusion) but, as I was writing this, I noticed @Dr.Peterson's post suggesting that the blue ball might have been thrown vertically upwards which means it would be constantly subjected to the same force (gravity) in the same direction (downwards).

If what you saw in the animation was the blue ball moving to the right and then reversing back to it original starting point then that might explain your confusion but is also consistent with what has now been suggested.

Hope that helps.

 

[Dr.Peterson]

If what you saw in the animation was the blue ball moving to the right and then reversing back to it original starting point

That is hinted at by the fact that we see only 5 locations rather than 9 as in the others; the blue ball was at locations 1, 2, 3, 4, 5, 4, 3, 2, 1 of the five. The black ball was at 9, 8, 7, 6, 5, 4, 3, 2, 1, moving to the left.

 

[The Highlander]

That is hinted at by the fact that we see only 5 locations rather than 9 as in the others; the blue ball was at locations 1, 2, 3, 4, 5, 4, 3, 2, 1 of the five. The black ball was at 9, 8, 7, 6, 5, 4, 3, 2, 1, moving to the left.

Indeed! Well spotted!