I can demonstrate my understanding of mechanical advantage

I can determine my mousetrap's mechanical advantage

• Mechanical advantage = ([length of metal spring-arm] / [length of extended mousetrap arm]) x ([Diameter of axle dowel] / [diameter of drive wheel])

Mechanical Advantage Conclusion

• The mousetrap car relies on a form of mechanical advantage to convert the fast burst of energy from the spring into a weaker but longer-lasting output of energy. The mechanical advantage can be calculated as follows:

• The metal spring-arm of the mousetrap is just 2" long and the craft stick mousetrap arm is 12" long, so the mechanical advantage of the extended arm is 2/12, or simplified as 1/6.

• This means that the force outputted at the end of the craft stick arm is 6 times weaker than the metal spring-arm, but it also travels 6 times farther.

• Additionally, the drive wheel dowel diameter is 0.25" and the wheel diameter is 4.75", so the mechanical advantage from the dowel to the wheel is 0.25/4.75 = 1/19.

• The total mechanical advantage can be calculated by multiplying the two: 1/6 x 1/19 = 1/114.

• This means that the force output at the outside of the drive wheels is 114 times weaker than the force at the end of the metal spring-arm, but it will also travel 114 times farther!

• 1/114 is a low mechanical advantage, meaning the output force is less than the input force. This is useful for mousetrap cars: a lower mechanical advantage means the energy from the mousetrap is used over a longer period of time so the car can be powered over a longer distance.

• By contrast, a high mechanical advantage would be useful if you wanted to move something heavy, but apply the force over a longer distance.

15 points: Student showed their work on how to find the mechanical advantage using the above example