Unit 1 Lab 1  Equations of Motion Lab
Unit 1 Lab 1: Equations of Motion Lab
Simulation: Equations of Motion Lab
Equations used in this lab:
Constant Velocity (zero acceleration): , , ,
Constant Acceleration: ,
When : ,
Centripetal acceleration:
Part 1: Motion where Acceleration is zero (Distance and Time)
1. Open the simulation: Equations of Motion
2. Change your car's Acceleration to 0 (m/s)/s and set the initial speed to any speed above 12 m/s to use for all trials in part 1 . After setting the Initial Speed, record the value in the top line of the table below.
3. Push down on the gas pedal for at least 20 seconds (time is indicated in simulated seconds by the simulation).
4. Make a screen shot of your simulation and paste it where indicated below. Show everything in the dotted lines.
5. Record the speed, distance, and time in the table below. Note: the distance is measured from rule marks at the front of the car. Estimate distance to the nearest 0.1 m.
This example shows the car at 425.6 m
Important: when recording data measurements from a simulation, never round digital readings. For example, don’t round a time measurement of 13.7 s to 14 s. Also, if you can estimate another significant figure, do so. For example, do not round the distance measurement shown in the picture above to 426 m. Estimate to 425.5 or 425.6 m.
The instructor will demonstrate with his own simulated data. Do not copy what the instructor gives as an example. Work with your own data. Also, do not copy data recorded by another student.
Screen shot and data table on next page.
Paste Screen Shot here.
Record your data in the table below. Use the formula to calculate the speed. Round the answer to the nearest one thousandth of a m/s. This means there should be 3 digits after the decimal point. If the last digit(s) is/are zero, write the zeroes in.
Distance 
Time 
Sim. Speed 
Calculated Speed. 




For the calculations below, use the simulation speed, not the calculated speed.
Simulation Speed (m/s) 
Time (s) 
Calculated Distance: . 




Distance (m) 
Calculated Time: . 



Results should be close to but not necessarily exactly the same as your measured values. If results are not close, troubleshoot your measurements and your calculations to find the error. Ask for help from the instructor if you cannot figure it out.
Part 2: Accelerated Motion
1. Click Reset. Raise your car's acceleration to some number greater than 0 (m/s)/s and less than 4 (m/s)/s. Set your initial speed to some value greater than 0 m/s and less than or equal to 10 m/s. Record the acceleration and initial speed setting at the top of the table below.
2. Click and hold the pedal until the speedometer is between 40 and 45 m/s.
3. Make a screen shot of your result and paste it below.
4. Paste Screen shot here.
5. Data Table for Results:
Acceleration (sim setting) 

Initial Velocity (sim setting), vi 

Final Velocity, vf 

Time, t 

Calculated Acceleration using formula: 

Make sure to include proper units with all numbers and follow rounding rules described in Part 1 for your calculation result.
Record your distance below and the compare that to the value calculated from the formula: .
It is always a good practice to write out your equation and then substitute the numbers into the equation, with units, before calculating the result. Then you can double check the whole process.

Simulation measurement 
Calculated value 
Distance 


Part 3: Accelerated Motion with Initial Velocity of Zero
1. Hit Reset and set your car's acceleration to some number greater than 0 (m/s)/s, but set your starting speed to 0 m/s. An acceleration between 3 and 5 (m/s)/s is recommended. Record the acceleration in the table below.
2. Push down on the gas pedal and hold it in place unit your speed is between 40 m/s and 45 m/s. Record your time, distance, and final speed.
3. Make a screen shot and paste it here.
Acceleration = (Sim setting) 


Time ( s), t 
Distance ( m), d 
Final Speed ( m/s), v 



4. Do the following calculations using your data.
Acceleration (sim setting) 

Time 

Calculate distance traveled using formula: 

Final Velocity using formula:


Make sure to put units with all numbers and round your calculation results as instructed in part 1. As before, calculated values should be close to measured values. If not, you either have the measurement wrong or you made a mistake in your calculation.
Part 4: Centripetal Acceleration
Open the simulation for the Circular Acceleration Lab.
Click the button for the app you are using (desktop or touch).
Select the option called “Polar Grid”.
The simulation shows a red line representing a car going in a circular path. Using the arrows you can adjust the speed and the radius of the car. We will be testing the formula for centripetal acceleration.
Adjust the simulation settings so the car is moving at a radius between 10 and 20 meters. Then adjust the speed so that the acceleration meter reads at least 2 m/s2. Record your radius, speed, and simulation acceleration reading in the table.
Make a screen shot of your simulation and paste it below.
Paste Screen shot here.
Radius ( m) 
Speed 
Sim Acceleration

Calculated Acceleration





Calculations: Use the formula (see above) to calculate the centripetal acceleration and enter your result in the table above. You can also adjust the simulation to determine the correct answer or follow the hints below.
If a car goes in the same circle at double its speed, by how much will the centripetal acceleration change? (Put an X in the yellow box by your choice.) Hint: double the speed used in your experiment and substitute that value into the formula to see how the calculated acceleration changes. 


a 
The acceleration will double. 

b 
The acceleration will quadruple. 

c 
The acceleration will not change. 

d 
The acceleration will be cut in half. 

e 
The acceleration will 1/4th of what it was. 
If a car goes at the same speed along a circle with double the radius, how will the centripetal acceleration change? (Put an X in the yellow box by your choice.) Hint: double the radius used in your calculation above and see how the acceleration changes. 


a 
The acceleration will double. 

b 
The acceleration will quadruple. 

c 
The acceleration will not change. 

d 
The acceleration will be cut in half. 

e 
The acceleration will 1/4th of what it was. 
Part 5 Newton’s First and Second Laws of Motion
Open the simulation: PHET Forces and Motion, Basics.
Click on the “Net Force” tab.
Check all the boxes to provide data for the net force and speed.
Click and drag a combination of blue and red figures to pull on the rope. The sum of forces value given by the simulation should not be zero.
Record your forces for the left and right in the Trial 1 row of the table below.
The force unit is called a Newton, abbreviated N. It is the standard metric unit of force, equal to about a fifth of a pound.
Force is a vector quantity, so you must indicate the direction in your measurement. Forces pointing to the left should be negative numbers. Forces pointing to the right should be positive. Record the unit (N) with each measurement.
Next click the Go! button and observe how the cart moves. Describe the motion, indicating the direction of motion (if any) and whether the motion appears to be a constant velocity or an increasing velocity.
For Trial 2, click Return. Then add or subtract figures so that the sum of the forces is zero. Record your forces. Click Go! and describe the motion.
Trial 
Left (negative) 
Right (positive) 
Sum of Forces 
Describe motion. 
1 




2 




Another way of describing the “ sum of forces” is the net force.
Based on these observations, complete each multiplechoice question, by typing an X in the yellow box of your choice.
When the net force on an object is zero, an object at rest will 

a 

remain at rest. 
b 

begin to move. 
When the net force on an object is not zero, an object at rest will 

a 

remain at rest. 
b 

accelerate from rest. 
c 

accelerate briefly before achieving and maintaining a constant velocity. 
One more trial: Adjust the forces so the net force is not zero, but make it so you can make the net force zero by adding or subtracting just one figure.
Click the Go! button and let the cart begin to pick up speed. Then pause the simulation and make the net force zero by adding or subtracting one figure. Then press Go! again and observe the motion.
When the net force on a moving object is zero, a moving object will 

a 

come to rest. 
b 

move at a constant velocity. 
c 

accelerate. 
If you chose the correct answers, you have discovered for yourself Newton’s 1st and 2nd laws of motion.
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Solution: Unit 1 Lab 1  Equations of Motion Lab