Rube Goldberg Project Rube Goldberg Paper Detail the
Rube Goldberg Project
Rube Goldberg Paper • Detail the energy transfers involved • Discuss the simple machines used • Include important design or production ideas • Include any physics concepts you had to consider while completing the machine • Not a description of the steps, rather a topical discussion of the physics involved.
Energy Transfers • For the Rube Goldberg machine to work, energy must be transferred from the beginning to the end. • Types of energy – Gravitational potential – Elastic potential – Kinetic – Linear - Chemical - Electrical - Thermal - Rotational
Energy Transfers • Potential to kinetic – Ball rolling down a ramp
Energy Transfers • Elastic to kinetic – Slingshot propelling a marble
Energy Transfers • Linear to rotational – Ball falling into basket connected to pulley
• A bar supported at a single point called the fulcrum. • Position of the fulcrum changes the mechanical advantage. • Manipulate the position of the fulcrum.
WHEEL & AXLE • Any large disk (the wheel) attached to a small diameter shaft or rod (the axle) • Can give you mechanical advantage. • Example: Turning a screw with a screwdriver
• Any rope or cable looped around a support. – Example: A rope thrown over a branch to hoist something into the air. • Often incorporates a wheel and axle system to reduce the friction on the rope and the support. • Gives mechanical advantage
• A ramp • Allows you to exert less force at the price of a longer distance • Same amount of work done, just seems easier because less force is needed.
• Two inclined planes placed back to back • May be forced into an object to prevent it from moving or to split it into pieces. • Example: A knife
• An inclined plane wrapped around a cone • Can be used to move a load (like a corkscrew jack) • Used to fasten objects together because of the great forces screws can exert
Complex Machines • Derived from simple machines • Combination and adaptation of simple machines
Mechanical Advantage • Simple machines can provide MA. • Ratio of output force to input force. • MA = Output force = Input distance Input force Output distance
Efficiency • Real machines have friction • Energy is dissipated as heat • Never 100% efficient • % Efficiency = Output work x 100% Input work
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