Physics 100 Chapt 10 Newtons Universal Law of Gravitation.

Slides:



Advertisements
Similar presentations
Circular Motion When an object travels about a given point at a set distance it is said to be in circular motion.
Advertisements

The law of gravitation By the end of this topic you should be able to:
Newton’s Law of Universal Gravitation
Newton’s Law of Universal Gravitation, Satellites, and Weightlessness
PHYS16 – Lecture 28 Ch. 13 Gravitation.
Universal Gravitation Newton Cavendish Examples Whiteboards.
Physics: Principles with Applications, 6th edition
Objectives: The student will be able to: 1.Apply the proportional relationship of the law of universal gravitation. 2.Use Newton’s second law and the law.
Newton’s Universal Law of Gravitation
Universal Gravitation
Physics I Honors 1 Specific Forces Fundamental Forces Universal Gravitation.
Gravity Chapter 7. Newton  Noticed the moon followed a curved path  Knew a force was required to allow an object to follow a curved path  Therefore,
Part 4 Newton’s Second Law of Motion Newton’s Second Law Acceleration is the rate at which your velocity (speed with direction) changes.
Universal Law of Gravitation Some Basics The force of gravity is the mutual attraction of objects to one another. The acceleration due to gravity.
Newton reasoned that there is a force of attraction between every two objects in the universe.
GRAVITATION 10th Grade – Physics 10th - Physics.
Universal Gravitation
Newton’s Law of Universal Gravitation
Newton’s Law of Gravitation. Newton concluded that gravity was a force that acts through even great distances Newton did calculations on the a r of the.
The Law of Universal Gravitation Isaac Newton’s Big Idea MoonApple Earth.
Newton’s Law of Gravitation. Newton concluded that gravity was a force that acts through even great distances Newton did calculations on the a r of the.
Gravity ISCI More Free Fall Free Fall Vertical and Horizontal Components of Free Fall.
Kepler’s first law of planetary motion says that the paths of the planets are A. Parabolas B. Hyperbolas C. Ellipses D. Circles Ans: C.
Newton’s Third Law of Motion Level 1 Physics. N.T.L Whenever one body exerts a force on a second body, the second body exerts an oppositely directed force.
Laws of Motion and Energy Chapter Seven: Gravity and Space 7.1 Gravity 7.2 The Solar System 7.3 The Sun and the Stars.
Fast Moving Projectiles: Satellites The Earth satellite is simply a projectile that falls around the Earth rather than into it.
Universal Law of Gravitation Some Basics The force of gravity (F g ) is the mutual attraction of objects to one another. The acceleration due.
GRAVITY What goes up, must come down??. Gravity Is it possible for some basketball players to “hang” in the air during a dunk? Give your opinion
One of the most significant intellectual achievements in the history of thought.
Newton’s Second Law of Motion. Newton’s Second Law Newton’s Second Law of Motion- Acceleration depends on the objects mass and the net force acting on.
Law of universal Gravitation Section The force of gravity: All objects accelerate towards the earth. Thus the earth exerts a force on these.
Proportionality between the velocity V and radius r
Satellites & “Weightlessness”. “Weightlessness” What keeps a satellite in orbit? The centripetal acceleration is CAUSED by the Gravitational Force! F.
Kepler’s Laws  Kepler determined that the orbits of the planets were not perfect circles, but ellipses, with the Sun at one focus. Sun Planet.
The Apple & the Moon Isaac Newton realized that the motion of a falling apple and the motion of the Moon were both actually the same motion, caused by.
Newton’s Law of Universal Gravitation
GRAVITATION NEWTON’S LAW OF GRAVITATION There is an attractive force between any two bodies which is directly proportional to the product of their masses.
C H A P T E R 4 Forces and Newton's Laws of Motion
What is the centripetal force acting on a 2000 kilogram airplane if it turns with a radius of 1000 meters while moving at 300 meters per second? a c =
Newton’s Universal Law of Gravitation. Questions If the planets are orbiting the sun, what force is keeping them in orbit? What force keeps the moon in.
If it is known that A is directly proportional to B, how would A change if B is increased by a factor of 2? 1. Increase by a factor of 2 2. Increase by.
PHYSICS 103: Lecture 11 Circular Motion (continued) Gravity and orbital motion Example Problems Agenda for Today:
Universal Law of Gravitation. Newton and Gravity Newton and the apple “If gravity attracts an apple toward the Earth, perhaps it also attracts the Moon,
The Force of Gravity. It is a centripetal force and it is provided by the gravitational force between the Earth & the Moon. What Type of force is this.
What holds us together? Gravity. Gravity is a force Force: a push or pull exerted on an object Gravity: the attractive force between objects; force that.
NEWTON’S LAW OF UNIVERSAL GRAVITATION Newton’s Law of Universal Gravitation.
Kepler’s Laws What are the shapes and important properties of the planetary orbits? How does the speed of a planet vary as it orbits the sun? How does.
Newton’s Universal Law of Gravitation
Gravity & Motion Unit 1 Lesson 4
The Force of Gravity.
Section 2 Newton’s Law of Universal Gravitation
Newton’s Universal Law of Gravitation
Your assignment is on the last slide
Newton’s Laws of Motion
Universal Law of Gravity
Universal Law of Gravitation
Universal Gravitation & Satellites
UNIT 3 gravitation.
Gravitation.
What is evident. The Earth and the moon have existed for about 4
Chapter 12 Section 2 Gravity and Motion.
Solution... Click for answers.
Universal Law of Gravity
Universal Gravitation
Laws of Motion and Energy
Newton’s Law of Gravitation
Newton’s Law of Universal Gravitation
Newton’s Law of Universal Gravitation
Gravitation.
Presentation transcript:

Physics 100 Chapt 10 Newtons Universal Law of Gravitation

Very fast horizontal toss t = 0s t = 1s x= 8km 5m t = 2s x=16km t = 3s x=24km 20m 45m V=8km/s

Orbital motion is free fall V = 4 km/sV = 6 km/sV = 8 km/sV = 10 km/s Circular Orbit!Eliptical Orbit

Centripetal acceleration a = v 2 /r for a circular orbit (v = 8km/s = 8x10 3 m/s) a = (8 x10 3 m/s) x 10 6 m = 64 x10 6 m 2 /s x 10 6 m = 10 m/s 2 Toward Earths center = g

Artificial satellite a v a = v 2 /r = g

Moon-earth v a=v 2 /r

Is the Moon in free-fall around the Earth? r=3.84x10 5 km v a = v 2 /r what is v? v = dist/time = 2 r 28d = 2 x 3.14 x 3.84 x 10 8 m 28d x (24h/d) x 3.6 x 10 3 s = 24 x 10 8 m 2.4 x 10 6 s = 1.0 x 10 3 m/s

Moons centripetal acceleration a moon = v 2 /r; v = 1.0 x10 3 m/s) a moon = (1.0 x 10 3 m/s) x 10 8 m = 1.0 x 10 6 m 2 /s x 10 8 m = 2.7 x m/s 2 Toward Earths center g

Newtons dreams Hmmmmm The Moon is in free-fall around the Earth Its acceleration is only 1/3600 g (accel at the Earths surface)

Distances r=3.84x10 8 m = 60 x 6.4x10 6 m The moon is 60x further from the Earths center than objects on (near) the Earths surface = 60 x R E ()2=)2= R E = 6.4x10 6 m

Newtons big idea The force of gravity gets weaker as distance squared The moon is 60x further from the Earths center than objects on (near) the Earths surface The strength of Earths gravity near the Moon is (1/60) 2 t=1/3600 times weaker

Gravity gets weaker as 1/dist 2

Universal law of gravity m M r F m F M F 1r21r2 combine:F mM r 2 F = G mM r 2 Proportionality constant: Newtons Constant

Universal Universal: applies to all objects!!!

What is G? W= G mM E R E 2 W W= m GM E R E 2 W= m g g=g= GM E R E 2

Force of gravity between ordinary-sized objects 80kg 60kg 1m F = G mM r 2 F = 6.7x Nm 2 /kg 2 60 kg 80kg (1m) 2 F = 6.7 x 60 x 80 x N Boys weight = mg = 80kg x 10m/s 2 = 800 N 30x10 9 times bigger! F = x N = 3.2x10 -7 N

Measuring gravity force between ordinary-sized objects is very hard

Moons gravity causes tides

So does the Suns Full Moon New Moon Half Moon

Measuring Weight mg N

Weightlessness N=mg N>mgN<mg N=0

Weightlessness means =0 N compensating upward

Weightlessness in action

Floating is space is really free-falling in space

What is g on the moon? W= G mM M R M 2 W= m GM M R M 2 W= m g M gM=gM= GM M R M 2 W R M =1.7 x 10 6 m m M

g M on the Moon g = GM M R M 2 6.7x N m 2 /kg 2 x 7.4x10 22 Kg (1.7 x 10 6 m) 2 = g M = 1.7 m/s 2 1/6 x g Earth

summary Obey the law!