Sunday, 3 April 2016

3 Designs of our car



Design 1

















 Design 2




And our selected car design :






Post PT discussion ( PT 2.5 )

Post-testing Discussion(PT 2)


1)Using your data table , calculate the average velocity for your mousetrap car during the best run in the final assessment.

Best Run : 4.06 meters in 7 seconds

Calculations :

                                The average velocity : 4.06 meters / 7 seconds
                                                                    =0.58m/1s

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

We feel that the lever of the car helped a lot with the distance it travelled. The use of a pen decreased and possibly removed any bending that might have been caused, reducing any wasted energy. Since the lever is longer than the trap, it increased the amount of string wound around the back axel, which in turn increased the distance travelled as the axel could turn more rounds.

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

The wheels of the car were not always aligned. We had difficulty in making the wheels parallel to each other and stay in that position. During one of the runs, the wheels did not travel in a straight line and were shaky, which reduced the distance that it could have travelled. Given more time, we would have thought of better solutions to overcome this problem.

The side support was not very strong as well, as it gave away the day before due to multiple testings and changes and we had to rebuild it. With more time, we could have found better and stronger materials to use as the support and main structure of the car.


Saturday, 2 April 2016

Construction of car ( PT 2.4 )

Dimension of car :

Width : 16cm
Length : 31 cm

Our car




























Video of our best run :








Engineering goals ( PT 2.2 )

Engineering goal

Design criteria :
After a lot of brainstorming,considering everyone's ideas and debating we have come to the conclusion that these will be our best design for our mousetrap car.


  • Mass : The mass of the car will immensely affect the distance travelled by our car.As most of us know,the mass is inversely proportionate to the acceleration.Lesser mass translates to lesser resistive force like friction.F=m x a so a = F/m.Lesser the mass more the acceleration and the further our car travels,hence we come to the conclusion that the mass of the car is important.
  • Wheels : The type of wheels will affect the resistance the car experiences and that will affect how far it travels.We must strike a balance between a really thick wheel and a super thin wheel.A thick wheel will cause too much resistance while a super thin wheel will make the car unstable and more force will be required to push the car as surface area is lesser and the force distributed is lesser too.We used discs which have lesser surface area in contact with the ground.To solve that problem,we put duct tape around the wheels to increase friction which will push our car forward.
  • Materials : The material of the car will affect the mass and the shape of the car too.Heavier the material,harder to make it move forward.Well with materials we also faced the problem of taking too much time to cut and saw it.This wastes time and reduces efficiency.
  • Length of rod/pen : At first we thought longer rod will cause the car to move forward faster and further but in the process of doing this we realised that we have to consider a lot of things.A longer arms will cause the car to travel further but slowly.Longer arms will pull the string more causing more rotations in the car.More rotations,further the car will go.A shorter arm will cause the car to move faster but not further.In this project we have to make the car go further and not faster so why not use a longer arm? Well,as the arm is longer,the car will travel slower.While travelling slowly the counter-force increases which will make the car stop even faster on a hard tarmac ground.A shorter one will be able to counter the counter-force and travel further but still we have to find a balance between both. 

Mousetrap car ( PT 2.1 )

Roles and Timeline(PT 2)

Wheel Engineer (IC of construction and testing) : Sean Ng Kai Kiat

- responsible for wheel choice and design
- sources materials for wheels
- works with Drivetrain Engineer to determine wheel-to-axle attachment

Drivetrain Engineer (IC of data analysis) : Kay Sandy Maung

- Responsible for developing system to transfer energy from the “engine” to the
wheels.
- Ensures proper testing and documentation of all drivetrain components.

Project Manager (IC of blog) : Siddhartha Jaruhar

- Responsible for all documentation and “care” of the mousetrap.
- Ensures that all tasks are completed and documented on time.
- Has final say on any issue that cannot be settled by consensus

Chassis Engineer (taken by the 3rd member if it is a 3-member team) : Fabian Heng

- responsible for the look and function of the body (chassis) of the car
- sources all materials for the chassis
- works with Drivetrain and Wheel Engineers to ensure function of wheels
and drivetrain components

TIMELINE:

1st Week : Discussion of things needed to be done and how.Design,materials etc.Which also includes buying the materials

2nd week ( March holidays ) :  Building parts slowly,troubleshooting problems and if needed brainstorming new ideas.

3rd week :  Complete the car.Troubleshoot final problems.Get all the documentations ready for the blog.

Saturday, 13 February 2016

The video and our bridge

Dimensions

Mass of bridge : 178 grams
Overall Length : 64 cm
Overall Width  : 5 cm
Overall Height : 8 cm



Calculation of efficiency

a) Mass of load on bridge : 5 kg
b) Mass of bridge : 0.178 kg
     Efficiency : (a)/(b)
                       =5/0.178
                       =28.1 ( 3 SF )