 Homework rubric

CP Sci 9- 1st Sem.

Gen Chem - 1st Sem.

Lab: Acceleration:

Problem:

You notice that when you place a ball on an inclined surface it rolls down hill.  Does it roll with constant speed or does it accelerate?  Why does it roll in the first place and what does it have to do with Newton’s laws of physics?  These are some of the observations you would use to form your hypothesis about acceleration and the slope of an incline.

What I expect:

Using the scientific method, perform a simple experiment and calculate the final velocity and the acceleration of a marble.

Procedure:

1)                  Obtain a meter stick, PVC tubing and a marble from your instructor.

2)                  Measure your piece of tubing from the pencil hole to the end of the tube. (Record the measurement in cm)

3)                  Set the initial height to 10cm.  (The next two trials should be at 50cm & 100cm)

4)                  Time the travel of the marble. (Remember to work as a team)

a.       One person releases the marble and holds the meter stick.

b.      One person times the marble.

c.       One person catches the marble.

d.      One person records the data.

5)                  Complete 3 trials for each measurement.

6)                  Repeat the experiment for the next two heights.

Measurements:

1)                  Distance the ball traveled. _________

2)                  Time it took the ball to travel the distance of the tube.

 Height Trial 1 Trial2 Trial3 Average

Formulas:

d = 1/2gt2

a = v/t

v = gt
Questions:

1)                  What was the average velocity at each of the three heights? (v = d/t)

A.

B.

C.

2)                  What was the acceleration of the marble in each of the three heights? (a = v/t)

A.

B.

C.

3)                  On graph paper, chart the following data using the values for acceleration that you calculated in question number two.

a.       Make a bar graph to display acceleration a different slopes.

i.      Slope = rise / run (vertical distance / horizontal distance)

b.      Make a line graph to display the distance the ball would travel at the rates of acceleration calculated in question 2.  Chart 1-10seconds. (d = ½ at2)

c.       Make a line graph to display the velocity of the ball at the rates of acceleration calculated in question 2.  Chart 1-10seconds. (v = at)  Acceleration                                  Distance

Slope                                       Time Velocity

Time

4)                  Compare your data with those of two other groups.  How do they compare? (similar or not)

5)                  What do you think could cause a difference in the results?

6)                  Do you think that your results are accurate? ( why or why not)

7)                  What do you think you could have done to improve the experiment?