What is My Rate?
Coding for the Core
Summer 2015
Initial hypothesis:
1. How do you expect the rotational velocity of the motor to be related to the
distance the robot travels in a given time period?
2. When we think about the distance the robot travels and the rotational
velocity of its motor, what are the dependent and independent variables?
3. Do you expect this relationship to be linear? Explain your reasoning.
4. How can you tell if a graph is linear?
What is My Rate?
Coding for the Core
Summer 2015
Data Collection and analysis:
Your robot has different speed settings: anywhere from 0 to 100. Let's see how
this influences the speed of the robot.
1. Run the programs in projects Speed20.ev3, Speed60.ev3 and Speed100.ev3.
Measure the distance the robot travels for each of these. Be sure to include
appropriate units.
Program
Speed20.ev3
Speed Setting
20
Speed60.ev3
60
Distance
Speed100.ev3 100
Time
5 sec.
Velocity
5 sec.
5 sec.
2. What do you think the distance and velocity will be at speed setting 0? Run
Speed0.ev3 to make sure.
3. Graph the relationship between the distance and the speed setting. Be sure to
place the independent variable on the horizontal axis. Label the axes on the
graph. Include your estimate for speed setting 0.
4. Is this graph linear? Explain your reasoning.
What is My Rate?
Coding for the Core
Summer 2015
5. Are parts of the graph linear? Explain your reasoning.
6. Using your graph, what distance would you estimate the robot would travel
in 5 seconds at Speed level 40?___________________
7. What distance would you estimate the robot would travel in 5 seconds at
Speed level 80?____________________
8. Explain how you calculated these estimates. Make sure to explain this clearly
so another student could follow your steps.
What is My Rate?
Coding for the Core
Summer 2015
9. Going back to your original data, calculate the velocity of the robot for each
speed setting. Be sure to include appropriate units.
10. Graph the relationship between the velocity of the robot and its speed setting.
11. Is this graph linear? Explain your reasoning.
12. Are parts of the graph linear? Explain your reasoning.
What is My Rate?
Coding for the Core
Summer 2015
13. Using your graph, estimate the velocity of the robot at Speed level
40.___________________
14. Estimate the velocity of the robot at Speed level 80.____________________
15. Run the programs in projects Speed40.ev3 and Speed80.ev3. Measures the
distance the robot travels and calculates the velocity for each of these. Be
sure to include appropriate units.
Program
Observed Distance Time
Observed Velocity
Speed40.ev3
5 sec.
Speed80.ev3
5 sec.
16. Determine the relative error, rounded to the nearest thousandth, of your
predicted distances. Use the following formula:
𝑅𝑒𝑙𝑎𝑡𝑖𝑣𝑒 𝐸𝑟𝑟𝑜𝑟 =
Program
Speed40.ev3
Speed80.ev3
|𝑎𝑐𝑡𝑢𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 − 𝑒𝑠𝑡𝑖𝑚𝑎𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒|
|𝑎𝑐𝑡𝑢𝑎𝑙 𝑣𝑎𝑙𝑢𝑒|
Observed Distance
Predicted Distance
Relative Error
What is My Rate?
Coding for the Core
Summer 2015
17. Determine the relative error, rounded to the nearest thousandth, of your
predicted velocities.
Program
Speed40.ev3
Observed Velocity
Predicted Velocity
Relative Error
Speed80.ev3
Conclusion:
1. If any of your relative errors is greater than 0.05, please discuss how the
error could have been created.
2. Explain why this information may be important in the real world. Please be
specific.