PT 2.4 - Testing Of Car


Actual Testing Of Mousetrap Car

Final Assessment
Mass of mousetrap car332 g
Mass of each wheelFront Wheel - 29gx2 = 58g
Back Wheels - 23gx2 = 46 g
Wheel diameter (Front)8.4 cm
Wheel diameter (Back)12 cm
Axle diameter0.4 cm
Length of string28 cm
Length of lever extension10 cm
Overall length30 cm
Overall width15 cm
Overall height12 cm

Test Run 1Test Run 2Test Run 3
Total time of test run / s
6
4
4
Total distance of test run / m
4
5
5.5
Observation 1: Was the car in steady and stable motion throughout?YesYesYes
Observation 2:
Was the car moving in a straight line mostly?
YesYesYes
Observation 3:
Did lever and string operate smoothly as well as expected?
YesYesYes

*Modifications were made in the personal testing of mousetrap car; under: "Construction of Car"*

TEST 1 

video


TEST 2


video


FINAL TEST 


video

Data analysis for Final run:
Velocity-Time graph

From t=1 to t=2.5, the car was accelerating at a decreasing acceleration.
From t=2.5 to t=3, the car was travelling at a constant speed of about 1.92m/s.
From t=3 onwards, the car was decelerating at a decreasing deceleration.

Distance-Time graph 
The car travelled 5.5 meters in 4.138 seconds.

 By using the formula 70-10p+2d-2(t-1),
Our total score = 70-10(0)+2(5.5)-2((4.138)-1) = 74.724





Post-Testing Discussion

Guiding Questions: 

1) Calculate the average velocity of your mousetrap car during the best run in the final assessment.

2) Which part of your mousetrap car design worked best? Explain your answer?

3) If you had more time to work on your mousetrap car, state and explain how you will improve/modify the current design?


Answers:


1) 1.33m/s

2) The lever arm worked the best. Since the original lever arm of the mousetrap is fairly short, it would pull on the string too rapidly, causing the wheels to slip and energy to be lost. For a steadier pull, we tried to attach an extended arm to act as the leverage, then tying the end of the string to it. It worked very well and lesser energy was lost, thus the mousetrap car went further than expected.

3) If we had enough time, we would have made a more efficient lever arm extension as we rushed the building of it due to the lack of time. As a result, it was not straight and it consistently affected the results; making the mousetrap car move to the side instead of moving straight ahead.

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