PhysicsLAB: LAB: Ramps - Accelerated Motion

Purpose: In this lab we will experimentally determine the fundamental properties of uniformly accelerated motion by using a ticker-tape time to analyze the motion of a cart down an incline plane.

Equipment:

4 meters of ticker tape
1 ticker tape timer with carbon disk
1 power supply
1 8-foot ramp
1 lab cart
1 meter stick

Procedure:

Connect your ticker tape timer to the power supply using the 0-24 volt DC output. Do not turn it on. Leave the adjusting knob at zero, its leftmost counterclockwise position, until we are ready to start the timer.
Thread the ticker tape through the two "guide staples" making sure that it passes underneath the carbon disk. The carbon disk should have its "ink side" down so that a mark will be made on the ticker tape each time the timer's rotating bead strikes it.
Attach one end of the tape to the lab cart and leave the other end free to slid through the timer.
When you are ready, call your teacher over to inspect your apparatus. If it is correctly set-up, you may then start the power supply.
Let the timer run and leave a preliminary "ink blob" of dots to mark the beginning of your experiment before releasing the cart.
As the cart rolls down the inline, it will pull the ticker tape through the timer leaving a set of "dots" along the backside of the tape.
Immediately turn off the power supply once the cart reaches the bottom of the incline.
Before allowing the next group to use the equipment, make sure that you can clearly see the dots on your ticker tape. If there is an error; complete another trial.

Data Charts:

Starting at the beginning of your tape, count the first 5 "discernible" dots - circling #5. Then count the next 10 dots, circling #10. Continue counting until you are done with all of the dots.
Measure the length of each 10-dot section and record their values as your cart's displacement during each interval.
For the purpose of this experiment, we will assume that your timer had a frequency of 20 hz. This means that each of your 5-dot sections represents 0.25 seconds.

Analysis:

Complete the remaining columns in your data table to calculate the average acceleration of your cart.
Enter the lengths of your 5-dot sections in the EXCEL graph provided. Save and print your graphs.

Conclusions:

1. Based on the shape of your EXCEL graph titled "Cumulative Distance vs Time" did your cart uniformly accelerate down the incline? Why or why not?

2. What was the numerical value of the slope of your EXCEL graph titled "Strip Length (Displacement) vs Group"?

2b. What does this slope represent?

3. What was the numerical value of the slope of your EXCEL graph titled "Average Velocity vs Time"?

3b. What does this slope represent?

4. Which of the following BEST describes the numerical relationship between your answers to questions #2 and #3?

slope #2 = 1/16^th x slope #3
slope #2 = 1/4^th x slope #3
slope #2 = slope #3
slope #2 = 4 x slope #3
slope #2 = 16 x slope #3

5. Why would you expect your answer to question #4 to be true?

6. According to your data table, what was your cart's average acceleration?

7. What is the percent difference between the average acceleration according to your data table (question #6) and the slope of the EXCEL graph of "Average Velocity vs Time" (question #3)?

8. What was the average length of three 5-dot sections at the end of your tape when the cart was traveling acooss the floor after leaving the ramp?

9. How fast was your cart moving as it traveled across the floor after leaving the ramp?

After submitting your results, turn in your completed data chart and a printout of your EXCEL charts.