Mousetrap Car Toy - Lab Report Example

Mouse and micetrap engineers and designers Your Workshop day Date Fun Time Toy Company The recipient’s address Dear Ms. Susan Brown RE: HIGH-SPEED MOUSETRAP CAR Regarding the high-speed mousetrap, here are the facts about it that might be of great interest to you. After several trials, tests, and modifications, the best model we successfully made has the specification as explained below. The least time of travel for a distance of 5m is 3.75s. The overall weight of the car is 0.14kg. The coefficient of the ground friction is 0.9 while the rolling resistance is 0.5. However, as the design was improved regarding performance, the cost kept on rising. The initial model cost 8.4 AUD while the last cost was 17.9 AUD. This model is very stable in that it cannot wobble and is also able to move in a straight line in addition to covering the distance of 5 m as required. This is the best design model whose high speed and performance outweighs the cost incurred. It has the best quality and form. If released into the market it would make great sale for your company. Kindly consider taking this design model for mass production. Yours Sincerely Your name Griffith School of Engineering Griffith University 1006ENG – Design and Professional Skills Semester 2, 2016 Mousetrap Car Your Name Goes Here (Include Full Name and Student Number) Your Team Identification Goes Here (Include the Workshop Day and Time) 1 Introduction 2 introduction There is a common way to make the mousetrap cars to move forward; that is by tying the one end of the string to the extended lever arm of the mousetrap and the other end on the axle of the wheels. The wheels get to move when the spring of the mousetrap is released. This is so because the lever arm pulls the string and in turn, wheels are made to rotate and therefore the car moves forward. There are many ways to convey the energy from the spring to the axle of the wheels creatively. When the mousetrap car is built mainly for speed, one may require the mousetrap to release the energy in the quickest way possible. The power output of the vehicle could be varied by adjusting the following; lever arm, diameter of the wheel and the axle diameter. When a shorter lever arm is used, the amount of energy is the same as that released when a longer lever arm is used. However, the length of the lever arm will adjust the power output. Lever arms when lengthened increases the distance of travel but the pulling force is reduced. Maximum power output is realized when the acceleration is highest. 2.1 Variables Important variables in this laboratory are few but very critical when it comes to the speed of the vehicle. These may include diameters of the wheel, the mass of chassis and the degree of the arm lever[Mer13]. These variables were changed and the distance travel was observed and recorded. This report consists of a letter to the client describing project briefly, introduction, discussion, conclusion and references. The following are the main objectives of this laboratory; 2.2 Objectives To design and make a very small car propelled by a mousetrap only. To learn about machines, how potential energy can be converted to kinetic energy simply by constructing mousetrap propelled car. To test the designed model and to make necessary adjustments until the car can travel a distance of 5m in the shortest time possible. 3 Discussion There are many forces that are in action as the mousetrap car decelerates or accelerates. However, these forces listed here are of greater significance to the analysis for this project; Applied force Rolling friction Normal force and gravity The angle at which the lever arm was pulled determined the amount of force generated by the mousetrap. The greater the angle of the pull the greater the force generated. If force is great so is the torque generated because torque is dependent on the arm of the lever and the force. Below is the equation of torque; T= Fr equation 1 Where F is the force, T is the torque and r is length of the arm lever. To change torque generated one would have to adjust either arm lever length, force applied or both. However, in this case, no adjustment would be made on the trap at all. Friction can be described as a type of force which opposes motion in any moving object. Energy is, therefore, necessary to first overcome the friction force and then to keep the object going. If the friction force is little then most of the energy stored in the spring will be used for propulsion and the vehicle is able to travel a very long distance[Mer13]. If friction is much, then the most of the energy stored in the spring would be used to overcome it and the vehicle travels a very short distance. For a fast moving object as our car, air friction affects distance traveled. Friction is a very important factor that has to be considered. Two types frictions will play a very crucial role here; dynamic and static friction. Static friction will come into play when the car was standing and dynamic friction when the car was in motion. Static friction does not depends on the surface area of the body. It heavily depend on the weight of the body and the type of materials on the rubbing surface. That is to mean that if one has a rectangular block, it would not matter with which side the block lies with, the effect of the friction will remain the same. Friction as seen above, has both positive and negative impacts on the project This is equation connecting friction force and the pulling force of the mousetrap; F=µN equation 2 Where f is pulling force, µ is the coefficient of friction and N is the weight of the car. Friction is not all bad since it will serve to ensure that the wheels do not spin on the same spot without moving forward. A very important equation which helped in design is first equation of motion by Newton; F=mc equation 3 Where c is the acceleration of the body, f is the force and m is the mass of the body and. Rotational inertia was another factor which affected the performance of the vehicle. If the vehicle has a very high rotational inertia, greater torque would be required which would translate to shorter arm lever. If the arm lever is short, so will the distance traveled by car. The following tools and equipment were used in the process; Stop watch Ticker timer Stop watch And meter stick Weighing balance A long piece of ticker tape was attached to the car. The importance of the ticker time was to help in the calculation of speed and distance. These formulas were used in calculation of speed and acceleration respectively; = = equation 4 = = equation 5 Four tests were done and results were recorded. A distance of 50 cm was used to help determine distance using the ticker timer. The ticker timer was set at a frequency of 60Hz. That is to mean that a mark is made on the tape after 1/60s. One end of the tape was labeled front and the other end rear. The tape was placed well so that it would not get tangled in the process of operation of the vehicle. The vehicle would be placed at the start line. With the ticker tape straightened, ticker timer is turned on and the vehicle is released simultaneously. The dark marks made on the tape, are labeled t0, t1, t2 to the end of the tape. The total time is t and the distance between the marks is and the total distance is d. The speed of the car was determined using equation 4. The following adjustment were made and then the above steps repeated to see how speed and the stability and the distance covered; Mass reduce by removing 2 acrylics attached to the sides Zip tie added to the rear axle Balloons added to the wheels Front replaced by those which were wooded and axle narrowed The above adjustment all led to improved performance of the vehicle in terms of stability speed and the distance covered. The best marketing strategy would be through advertisement to reach young people. This can be done on social media and most young people would get reached. 4 Conclusion. After the series of tests and modifications, a prototype which meets the requirement was achieved. The first model which was the cheapest was also the heaviest and did not reach the expected distance of 5m. The second model was lighter compared to the first model. It would reach the expected distance of 5 m but it was slower. It was more expensive compared to the first model. Balsa wood was also used here. The third model was almost like the final one only that it was not as refined and expensive as the final one. The cost of the third model was 14.4 AUD, mass of 0.177kg. The final design model had a mass of 0.14kg, cost was 17.9 AUD. It took only 3.75 seconds to cover the distance of 5m. In other words, the final model was the finest although a little expensive. Therefore, this design could be adopted for mass production. Its feature, appearance and performance guarantees high sales in the market. Errors were eminent in the project because of the little time. Thus, everything was done in a hurry. Therefore given more time a better design could have been realized. Errors also could have resulted from use of instruments that were faulty or which have not been calibrated for a very long time. 5 Reference Mercer, B. (2013). The racecar book: Build and race mousetrap cars, dragsters, tri-can haulers & more. Read More