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The Requested Universe. Section 2. Why do planets seem to meander gradually over the sky?. Newton's laws of movement and gravity foresee the conduct of articles on Earth and in space. The Night Sky. Development of stars, planets, sun Physical occasions are quantifiable and in this way unsurprising.

Transcripts

The Ordered Universe Chapter 2 Why do planets seem to meander gradually over the sky? Newton\'s laws of movement and gravity anticipate the conduct of items on Earth and in space

The Night Sky Movement of stars, planets, sun Physical occasions are quantifiable and subsequently unsurprising

Stonehenge Started in 2800 B.C. in south England: Built over long time by various individuals, none had a composed dialect, some even needed metal apparatuses. Marks entry of time, particularly the seasons. Still capacities today. The biggest stone, around 10 m long, weighted 50,000 kg (100,000 lb), were moved 30 km (20 miles).

Stonehenge : How to construct it by individuals then?

The Discovery of the Spread of Disease of Cholera In nineteenth century, John Snow: Observation, distinguished an example, made a recommendation (theory), demonstrated the expectation.

The Birth of Modern Astronomy Historical Background: Ptolemy & Copernicus Ptolemy second century A.D. In the first place planetary model Earth at focus, stationary Stars and planets spun around earth Copernicus Ideas distributed in 1543: On the Revolutions of the Spheres Sun at focus: Is it conceivable to build a model of the sky whose expectations are as precise as Ptolemy\'s, however in which the Sun, as opposed to the Earth, is at the middle?

Observations: Tycho Brahe & Johannes Kepler Tycho Brahe (1546-1601) Observed and found another star Designed and utilized new instruments Collected precise information on planetary development Johannes Kepler (1571-1630) Kepler\'s Law of Planetary Motion: 1. Planets all move in circular circles about the Sun, with the Sun at one concentration of the oval. 2. The span vector attracted from the sun to the planet clears out equivalent ranges in equivalent circumstances. 3. The shape of the normal sweep about the sun for every planet is relative to the square of the time of the circle.

The Birth of Mechanics Galileo Galilei (1564-1642) Mechanics: movements of material articles Galileo Invented numerous commonsense gadgets, for example, thermometer, pendulum clock, compass, and so forth. Was the first to record perceptions of the sky with a telescope The Heresy Trial of Galileo

Speed, Velocity, and Acceleration Speed: separate went after some time Velocity: speed with heading Equation for speed or speed: Acceleration: rate of progress of speed Equation for increasing speed:

The Founder of Experimental Science Galileo Relationship among separation, time, speed and quickening Found articles quicken while falling

Falling Objects Constant quickening Balls on a plane with an incline: v=at d=½at 2 Freefall Constant speeding up at g =9.8 m/s 2 = 32 feet/s 2 Velocity v=gt Distance voyaged d=½gt 2

Examples Ex2-1. On the off chance that your auto voyages 30 miles for each hour, what number of miles will you go in 15 minutes? Ex2-2. A sprinter quickens from the beginning squares to a speed of 10 meters for each second in one moment. Answer the accompanying inquiries concerning the sprinter\'s speed, increasing speed, time, and separation. For each situation, answer the question by substituting into the suitable movement condition. 1. What is his quickening? 2. How far does the sprinter go amid this 1 second of quickening? 3. Accepting the sprinter covers the rest of the 95 miters at a speed of 10m/s. What will be his time for the occasion? Ex2-3. The tallest working in the United States is the singes Tower in Chicago, with a tallness of 1454 feet. Overlooking wind resistance, how quick would a penny dropped from the top be moving when it hit the ground?

Isaac Newton and the Universal Laws of Motion A moving item will keep moving in a straight line at a steady speed in a similar course, and a stationary question will stay very still, unless followed up on by an unequal constrain. Illustrations Uniform movement and quickening Force Inertia The principal Law

The Second Law The increasing speed delivered on a body by a drive is corresponding to the extent of the constrain and contrarily relative to the mass of the question Equation: F=ma Example: What is the compel expected to quicken a 75 kg sprinter from rest to a speed of 10 m/s in a half second?

The Third Law For each activity there is an equivalent and inverse response. Condition: F 1 = - F 2 Examples:

Newton\'s Law at Work

Examples Ex2-4. What is the constrain expected to quicken a 75 kg sprinter from rest to a speed of 10 meters for every second (a quick keep running) in a half second?

Momentum relies on upon mass and speed Linear force : p=mv Conservation of straight energy Examples (Ex2-5): A baseball with mass 0.3 kg moves to one side with a speed of 30 m/s. What is the energy?

Angular energy A protest that is pivoting will continue turning unless a winding power acts to change it. The curving power is known as a torque. Protest with more mass, or with mass found more remote far from the focal pivot of revolution have more prominent rakish force. Protection of Angular energy, Examples

The Universal Force of Gravity Newton\'s law of widespread attraction F=Gm 1 m 2/d 2

The Universal Gravitational Constant, G: general steady First measured by Henry Cavendish G=6.67 x 10 - 11 m 3/s 2 - kg or 6.67 x 10 - 11 N-m 2/kg 2 The estimation of the G is proportional to the estimation of the mass of the Earth.

Weight and Gravity Weight The drive of Gravity following up on a protest. Weight relies on upon where you are Different on earth versus moon Mass is the measure of matter, which remains the same wherever you are

Big G and Little g Closely related: Weight on Earth = (G x mass x M E )/R E 2 Weight on Earth = mass x g Setting conditions break even with: g= (G x M E )/R E 2 The mass of the Earth is 6.02x 10 24 Kg, and its sweep is 6370 km. Connect to numbers, g = 9.8m/s 2 Example (Ex2-6) : The mass of moon is 7.18x 10 22 Kg, and its sweep is 1738 km. On the off chance that your mass is 100 kg, what might be you weight on the moon?

Problems (p47) 1. On the off chance that a man weighs 150 pounds, what does he weight in Newtons? 2. In the event that your auto goes from 0 to 60 miles for each hour in 6 seconds, what is your speeding up? In the event that you venture on the brake and your auto goes from 60 miles for every hour to 0 in 3 seconds, what is your quickening? 3. What amount of compel would you say you are applying when you lift a 50-pound dumbbell? What unit will you use to portray this compel? 4. What might you weight on Venus? On Saturn?