cq_1_031

#$&*

phy 231

Your 'cq_1_03.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** **

Copy the problem below into a text editor or word processor.

• This form accepts only text so a text editor such as Notepad is fine.

• You might prefer for your own reasons to use a word processor (for example the formatting features might help you organize your answer and explanations), but note that formatting will be lost when you submit your work through the form.

• If you use a word processor avoid using special characters or symbols, which would require more of your time to create and will not be represented correctly by the form.

• As you will see within the first few assignments, there is an easily-learned keyboard-based shorthand that doesn't look quite as pretty as word-processor symbols, but which gets the job done much more efficiently.

You should enter your answers using the text editor or word processor. You will then copy-and-paste it into the box below, and submit.

________________________________________

The problem:

A ball starts with velocity 0 and accelerates uniformly down a ramp of length 30 cm, covering the distance in 5 seconds.

• What is its average velocity?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

The average velocity is the change in distance/change in time = (30 cm - 0 cm)/5 seconds = 6 cm/s.

#$&*

• If the acceleration of the ball is uniform then its average velocity is equal to the average of its initial and final velocities.

You know its average velocity, and you know the initial velocity is zero.

What therefore must be the final velocity?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

v_Ave = (vi + vf)/2, therefore vf = 2*v_Ave - vi = 2*(6 cm/s) - 0 cm/s = 12 cm/s or twice the average velocity.

#$&*

• By how much did its velocity therefore change?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

It’s velocity changed from 0 cm/s to 12 cm/s over a time interval of 5 seconds.

#$&*

• At what average rate did its velocity change with respect to clock time?

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

Its average rate of change is therefore (12 cm/s - 0 cm/s)/5 seconds = 2.4 cm/s^2

#$&*

• What would a graph of its velocity vs. clock time look like? Give the best description you can.

answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):

The graph of velocity vs. clock time would have clock time on the x-axis and velocity on the y-axis. The plot would be a straight line starting at time 0 and velocity 0. It’s slope would be 2.4 cm/s^2 because the rise would be the change in velocity and the run would be the change in time, which is the average rate of change of the velocity.

#$&*

*#&!*#&!

&#Your work looks very good. Let me know if you have any questions. &#