Introduction
A mouse-trap car according to Balmer (1998) is a kind of motor vehicle that is motorized by the power that is accumulated in a wound up mouse-trap spring (1). A simple mouse-trap is constructed by attaching a string on a mouse-trap’s snapper arm and then winding this string on a drive axial by spinning the wheels in the reverse direction to the mouse-trap’s car projected motion. Once winding is complete, the springs of this car will be under tensional force and as a result potential energy is stored.
On releasing drive wheels, string wound on the drive axial is pulled off and as a result, the wheels and drive axial will begin to revolve, pushing the vehicle forward i.e. the potential energy stored in the wound springs is converted into kinetic energy. This is a basic mouse-trap car and will move for few meters before stopping. Since the snapper which is the load in the mouse-trap car is at the end while the effort force which is the spring arms is in the middle between the load and the fulcrum, mouse-trap car is classified as a third class lever (Home Training Tools, 2011).
Motion of Mouse-trap Car
In principle, Newton’s first law apply to mouse-trap car whereby before releasing this car, it will remain at rest and once released, it will have a tendency to continue moving except when acted on by exterior opposing force. When designing them, care is taken to minimize the inertia by building a light car that will move with ease. If potential energy of the car is released rapidly, the rate of acceleration will be high and car will run faster.
Unfortunately this is not good since the car will run short of energy quickly and stop. In contrast slow release of energy implies the car will ran slowly but for a longer time. When designing mouse-trap car the lever arm is lengthened by fixing a rod or pencil to the snapper arm and fastening the thread to the end of snapper arm. By doing this, “longer piece of thread is used as compared to when you tie the thread directly to the snapper arm” (Home Training Tools, 2011, par.6).
Importance of Making Mouse-Trap Car
To make a “great” mouse-trap racer, we not only try to determine and make necessary adjustments but must also strike a balance between all changeable and constituents that will either directly or indirectly affect the performance of this car. Mouse-trap cars are commonly used in physics lessons to assist students in developing problem-solving abilities, become skilled planning their managing time, expand spatial responsiveness and practice accommodating manners as they work together.
Factors affecting Mouse-Trap’s Performance
Different variables such as the diameter of drive wheels frictional, the length of the mouse-trap’s level arm, and the size of drive axial affect the performance of this car.
Mechanic advantage affects the performance the car. Varying the diameter of either the axle/hinge or the wheel changes the mechanical gain of the hinge-wheel coordination. According to Fizzix (2005), “when the ratios of the length of string used per turn divided by the distance traveled is less than one, the mechanical advantage is small and the car travels slow and far”(p.1). If the quotients of the measurement lengthwise of threat applied per turn divided by the distance covered is more than one, the mouse-trap car gathers speed very rapidly and utilizes merely a centimeters of the thread. Transmission is characterized by the diameters the drive axis and drive wheel(s) (Fizzix, 2005; Parker, 2007).
The bigger the diameter of the driven pulley is, the bigger the mechanical advantage of the car. A big wheel or tire with a tiny axle or axis will cover a bigger distance for every rotation of the axis when weighed against a lesser wheel with the identical axis or axle. However there is an exchange for including a big wheel-to-axle ratio.
The trade-off in such case is that much force is required to speed up the mouse-trap car to the matching velocity in the equivalent time as a car that has a small wheel-to-axis quotient, even though this not a problem since cars that travel for a long distance need not be fast so as to minimize fluid friction force (GatorTrax Engineering, 2004). According to Barry (2007), “it is critical that a car with a big wheel-to-axle ratio has a small revolving inertia wheel, since low rotational inertia wheels will be much easier to rotate than large rotational inertia wheels” (p.7).
Conclusion
Mouse-trap is a simple third class level car that moves when potential energy stored in the spring is converted into kinetic energy as the spring unwinds. Different variables such as the length of the mouse-trap’s level arm, the diameter of drive wheels, and the size of drive axial affects its performance and therefore care should be taken when constructing designing this kind of the car. Mouse-trap cars are commonly used in physics lessons to assist students in developing problem-solving abilities, become skilled planning their managing time, expand spatial responsiveness and practice accommodating manners as they work together.
Experiment
Purpose of the experiment
To establish how change in the size of the wheels of the mouse-trap car affects the distance covered
Hypothesis
A mouse-trap car with the largest wheels covers the biggest distance
Materials Used
Tape measure, smooth table or smooth ramp, and 3 cars with different wheel size
Procedure
- Each of the three cars is placed on a line marked “start” and then released one at a time
- It is then left to run until it stops and then tape measure used to measure the distance covered. Error allowed is 1 inch
- The results are then Tabulated as below
Observations and results
Conclusion
It was found out that the car with largest wheel covered the biggest distance while the car with the smallest wheel covered the smallest distance.
References
Balmer, Alden J. (1998). Mousetrap powered cars and boats. New York, NY: Prentice Hall.
Fizzix, Doc. (2005). Mouse Trap Cars and Racer Gearing. Web.
GatorTrax Engineering. (2004). Instructions for making a simple mousetrap car. Web.
Home Training Tools. (2011). Mousetrap Physics. Web.
Parker, Barry. (2007). Science: 101 physics. New York, NY: Harper Collins Publishers.