Bell-Ringers 16 June 2009
The Prediction • “Give me a place to stand and a lever long enough and I will move the earth.” • Do you think this is possible? Why or why not?
Astronomers know the earth's mass. On earth a body possessing such a mass would weigh in round numbers 6,000,000,000,000,000,000,000 tons
Supposing a man could lift only 60 kg directly, to "lift the earth" he would need a lever with a long arm that would be longer than the shorter arm by 1,000,000,000,000,000,000,000 times!!
You can easily figure it out that to have the end of the short arm rise by one centimeter; the other end must describe through space the huge arc of 1,000,000,000,000,000,000 km
Presuming Archimedes could have lifted 60 Kg one meter in one second- the work of almost one horsepower! - to lift the earth by just one centimeter, even then he would need 1,000,000,000,000,000,000,000 seconds (30 million million years).
Even if Archimedes had been able to push the lever with a speed of 0.34 km/sec the speed of sound, he would have lifted the earth by one centimeter only after 93,264,094,069,895.84265 years
If he had pushed the lever with the speed of light, 300,000 km/sec, natures fastest possible- he would have lifted the earth by one centimeter only after ten million years of pushing.
Bell-Ringer • 17 June 2009 • Learning Target: Explain how inclined planes make work easier. • Name one inclined plane that you used today.
Bell-Ringer 17 June 2009 Learning Target: Identify properties of polymers and metals. What is a “polymer”? What is a metal?