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Engr3 Name ___HANG NGUYEN______________
Mission College
Dissect a Toy Car
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Equipment Needed:
Schylling Toy Cars with Flywheels
Philips Screw drivers (small)
Introduction:
In this lab you will dissect a child’s toy car with a flywheel. These common toys allow the child to “rev up” and energize the car so that the car when put down will go on its own or even climb an incline. Energy is stored in the car because of the flywheel - a massive, metal disk that has inertia. Once this metal disk is moving it tends to continue to rotate and as a result it releases its kinetic energy over time by driving the wheels of the car. The entire process works as follows: The child moves the wheels and the wheels in turn drive the flywheel and give it kinetic energy, then once the car is set down, the energy flows from the flywheel to the wheels.
The kinetic energy stored in the flywheel is similar to ½ mv2, however the actual equation is different because the flywheel rotates instead of moves in a straight line. The equation is ½ I Φ2. I is the rotational inertia (think if this as the flywheel’s mass) and Φ is the speed of rotation (think of this as the speed of the flywheel).
Since Φ is the term that is squared, then it is very important that speed of the disk be high if you want to store a lot of energy in a toy car. The mass is important too, but obtaining speed is the most important factor for storing kinetic energy in a flywheel.
Another consideration is that if the flywheel is too massive it becomes hard to turn and energize and the forces on the gears become too high for inexpensive plastic parts. So as you increase and improve the flywheel’s energy storage capabilities by increasing the flywheels mass you degrade another aspect of the car’s performance.
Creating a toy car involves understanding both the limitations of your parts and the design trade-offs.
Before you do the dissection, play...
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