Pendulum Motion
Q1. Outline the historical development of the models of the universe from the time of Aristotle to the time of Newton.
Aristotle: Geocentric model of the universe involved a series of 56 concentric spheres to which celestial objects were attached. The Earth was not in motion as the stars showed no measureable parallax. Each planet, the Sun, and the Moon were in their own sphere and the stars were positioned on a larger sphere surrounding all the others.
Ptolemy: Geocentric model of the universe placed the Earth at the centre of the universe with the heavenly bodies moving around on a series of small spheres or circles called epicycles. The stars moved on a celestial sphere around the outside of the planetary spheres.
Copernicus: Heliocentric model of the universe placed the sun at the centre of the universe. In this model planets still executed uniform circular motion around the sun. Also the Moon orbited the Earth.
Kepler: Heliocentric model of the universe placed planets in an elliptical orbit around the sun. The planets sweep out an equal area in equal time as they orbit the sun. The ratio of the cube of the radius to the square of the period of the orbits is equal for all planets in our solar system. These requirements of the universe model became known as the three laws of planetary motion.
Galileo: Heliocentric model of the universe that was proved by the discovery of four moons orbiting Jupiter, which showed that there were other centers in the heavens beside the Earth. Also Galileo discovered that Venus went through phases like the moon proving it orbited the sun. The Catholic Church claiming heresy persecuted him for his findings.
Newton: Heliocentric model of the universe. Created the theory of universal gravitation and used it to explain the motion of the planets and moons. Discovered that gravity was the force that controlled the orbits of the planets around the sun and the moons around the planets.
Q2. Outline the discovery of
Aristotle: Geocentric model of the universe involved a series of 56 concentric spheres to which celestial objects were attached. The Earth was not in motion as the stars showed no measureable parallax. Each planet, the Sun, and the Moon were in their own sphere and the stars were positioned on a larger sphere surrounding all the others.
Ptolemy: Geocentric model of the universe placed the Earth at the centre of the universe with the heavenly bodies moving around on a series of small spheres or circles called epicycles. The stars moved on a celestial sphere around the outside of the planetary spheres.
Copernicus: Heliocentric model of the universe placed the sun at the centre of the universe. In this model planets still executed uniform circular motion around the sun. Also the Moon orbited the Earth.
Kepler: Heliocentric model of the universe placed planets in an elliptical orbit around the sun. The planets sweep out an equal area in equal time as they orbit the sun. The ratio of the cube of the radius to the square of the period of the orbits is equal for all planets in our solar system. These requirements of the universe model became known as the three laws of planetary motion.
Galileo: Heliocentric model of the universe that was proved by the discovery of four moons orbiting Jupiter, which showed that there were other centers in the heavens beside the Earth. Also Galileo discovered that Venus went through phases like the moon proving it orbited the sun. The Catholic Church claiming heresy persecuted him for his findings.
Newton: Heliocentric model of the universe. Created the theory of universal gravitation and used it to explain the motion of the planets and moons. Discovered that gravity was the force that controlled the orbits of the planets around the sun and the moons around the planets.
Q2. Outline the discovery of