Pt2.4 - Testing Of Car

2.2 Testing & Modification
Total Time of test run: 5 Seconds
Total distance of test run: 293 cm
Observation 1 (Was the car in steady and stable motion throught):
The car was not steady and stable in motion and its wheels swayed from side to side, causing an increase in friction. This led to the resultant force of the car being decreased and the car covering a smaller distance.
Observation 2 (Was the car moving in a straight line mostly):
The car was more stable but still tended to turn towards the right.
Observation 3 (Did lever and string operate smoothly as well as expected?
The lever and string operate smoothly as expected. No Faults present
State 1 Area  for modification:
The wheels can be made out of a material which is not a ‘CD’ because of its small edges which cause it to be unstable and wobble. However, current we do not have the proper material hence. What we did is that we place straps on both sides of each wheels to ensure that the the wheels remains stable and lock in position.
State rationale/reason(S) for the above proposed modification:
The straps help to lock on to the wheels ensuring it remains in position.


2nd test (https://youtu.be/d0NfEWWyUtE) Best Run
Total Time of test run: 4 Seconds
Total distance of test run: 399 cm
Observation 1 (Was the car in steady and stable motion throught):
Although the car was still not very steady & stable enough, it was much better when compared to the previous test as straps were placed on both sides of the wheels allowing it to travel a further distance
Observation 2 (Was the car moving in a straight line mostly):
The car was moving in a straight line but it movie toward the left-hand side of the releaser perspective.
Observation 3 (Did lever and string operate smoothly as well as expected?
The lever and sting operate smoothly as expected. No Faults present.
State 1 Area  for modification:
We thought that to increase the distance travelled by the mouse trap car, we can decrease the length of the string connecting the rod to the mouse trap.
State rationale/reason(S) for the above proposed modification:
We decrease the length of the string to try out whether it affect the experiment.


Total Time of test run: 5 Seconds
Total distance of test run: 375 cm
Observation 1 (Was the car in steady and stable motion throught):
Although the car was still not very steady & stable enough, it was much better when compared to the test 1 as straps were placed on both sides of the wheels allowing it to travel a further distance
Observation 2 (Was the car moving in a straight line mostly):
The car was moving in a straight line but it move a little to the left-hand side from the releaser perspective.
Observation 3 (Did lever and string operate smoothly as well as expected?
The lever and sting operate smoothly as expected. No Faults present.


State 1 Area for modification:
No area of modification done as last test.
State rationale/reason(S) for the above proposed modification:


No area of modification done as last test.


3.1. FINAL ASSESSMENT DATA TABLE


Run Number (Max. 3 trials)
Trial 1
Trial 2
Trial 3
Total time of Run / s
5
4
5
Total Distance of Run / m
2.93
3.99
3.75
Total Score
70-10(0) +2(2.93/0.5) -2(5-1)
=
73.32
70-10(0) +2(3.99/0.5) -2(4-1)
=
79.96
70-10(0) +2(3.75/0.5) -2(5-1)
=
77


3.2 Post-testing Discussion
  1. Using your data table from the Final Assessment, calculate the average velocity for 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?
1. Velocity for 1st test: 2.93/5 =0.586 m/s
Velocity for 2nd test: 3.99/4 =0.9975 m/s =0.998 m/s (3 s.f.)
Velocity for 3rd test: 3.75/5 =0.75 m/s = 0.750 m/s (3 s.f.)


Average velocity= (0.586 m/s + 0.9975 m/s + 0.75 m/s)/3 = 0.778 m/s (3 s.f.)


2. Our Car is more streamlined allowing it to reduce air resistance (Which is an opposing force) which enable the car to travel faster and cover a longer distance.


The Wheels are thin and do not have much surface area in contact with the ground, addition, we place a rubber sheet on the edges of the wheels. Hence, with this we are able to reduce the friction opposing the motion of the car, enabling it to travel further as it requires less force to move.


For the Lever arm, we decide to use a much longer lever arm as when we have learn from our lesson about turning point. The longer the perpendicular distance between the point where force is applied and the pivot, the less amount of force is required to be applied.


3. The first thing that can be improve is the amount of wheels that are present in the mouse trap car. By reducing the amount of wheels to 3, we can reduce the amount of friction that is opposing the direction of the car as there are lesser surface into contact with the ground.
Secondly, we can increase the diameter of the wheel(s) that move by the string of mouse trap as with a large wheel, with each and every 1 turn, a large distance will be covered by the large wheel as compared to the smaller wheel enabling the car to travel a large distance.
Additional, we can increase the length of the mousetrap rod that is connected with the wheels rod as when we have learn from our lesson about turning point. From the longer the perpendicular distance of the string point (Force applied) to the turning point require a lesser amount of force is required to move. Hence, with a lesser amount of force need, the object can travel further.
Also, we can change the wheels instead of using CD, a wheel that is a little more thicker as it helps to provide stability to the wheel ensuring will not wobble. As a thinner wheel will wobble frequently and lose much of the force pushing it hence reducing distance that can be traveled. Although the increase in thickness of will increase the amount of friction that is opposing motion, we value stability over trying to reduce friction as stability will allow the car to travel further compared to reducing a little friction.

1 comment: