Created by Allison Neal and Rachel Laviolette for our Physics 142 class.

1. Physics 142
Extra Credit Project
By: Rachel Laviolette
And Allison Neal

2. What concept did we miss on
the test?
On test two we missed question
number three.

3. Question #3
 A ball moves in a curved path inside of a curved
tube. The ball is inside the tube at three different
times. The arrows represent the speed of the ball
at those three times.
At time 2 is there an unbalanced force acting on
the ball? If yes, add an arrow to the picture to
show the approximate direction of the unbalanced
force, and briefly justify your answer. If no,
explain why not.

4. Why we had trouble with this
concept
 Rachel- I thought the ball moved
because it was in a tube, and I
thought it was following the tube.
 Allison- I thought there was a
balanced force acting on the ball,
since it was traveling at constant
speed inside the curved tube.

5. Newton’s Second Law
 Why does this help us understand?
 Newton’s second law tells us that
forces push and pull on an object
making the object move in the
direction of the force. The stronger
force would overcome the lesser
force, causing the object's motion to
go in the direction of the stronger
force.

6. Relates to the problem
Newton’s second law relates to
our question because the
direction of the ball changes, so
we know there must be a new,
stronger force acting on the ball,
making the ball move in its
direction.

7. Evidence
 Chapter 2 activity 6 homework.
 We used the simulator and saw that
when the soccer ball was tapped in
a direction the ball moved in the
direction, it was tapped.
 http://cipstrends.sdsu.edu/petsims/s
imulators2/simulators/c2a6hws1.ht
m

8. Rachel’s Narrative
 There was an unbalanced force acting on the ball
as it traveled at a constant speed through the
tube. I would draw the arrow over time point #2,
because that is where the unbalanced force is
acting on the ball. Newton’s Second law explains
that the ball will move in the direction of the
stronger force.
 The part that confused me about the questions
was that I thought the ball moved because it was
in a tube. However, I now understand that the ball
was moving in the direction of the unbalanced
force, which was the stronger force.

9. Allison’s Narrative
As the ball traveled through the curved tube at
Time #2, there was an unbalanced force acting
on the ball. The main concepts that were covered
in Question #3 included friction and Newton’s 1st
and 2nd Laws of Motion. Where I messed up was
not taking the second, and apparently much
stronger force, into account. The friction from the
ball contacting the sides of the tube as it was
given no choice but to curve, was indeed stronger
than the original driving force. After discovering
this, I would advise other students to pay
excellent attention to Newton’s Laws of Motion.
They easily explain the relationships between
moving objects and the opposing forces that act
upon them.

10. Conclusion
 In conclusion, we realized that if the
direction of the ball changes, there
is an unbalanced force acting on
the ball. Even if the speed remains
the same, the changing of
directions is a way to know an
unbalanced force is acting on an
object.

11. Reviews
 We want to thank Blair McKee and
Minnie Gatlin for reviewing our extra
credit project for us. They agreed with
our explanation of question number
three.