Imagine a universe where the force of gravity
- Slides: 38
Imagine a universe where the force of gravity is repulsive, not attractive as it is in our universe. What would that universe be like?
It would be like this, only without the stars. Everything would be hydrogen gas.
Ok, what would the universe be like if gravity was attractive, but was billions of billions times stronger?
Much flatter than pancakes!
Now, what would the universe look like if there existed a force, that was both repulsive and attractive, and trillions of times stronger than gravity?
It would look like this! We call such a force the Electric Force
Science knows of four forces that exist in nature. The Strong Force The Weak Force. The Electromagnetic Force Gravity The strong and weak forces are short range forces, that is, they only act over very small distances (like inside the nucleus of an atom). Gravity and the electromagnetic forces are long range forces and can act over very large distances.
Perhaps the most startling thing about the electric force is how strong it is compared to gravity It is approximately 3 x 1047 times stronger than gravity. Actually, it’s not that the electric force is so strong, it’s that gravity is so weak.
Rules of Electrostatics 1. There are two kinds of charge that exist in nature (positive charge and negative charge) • unlike charges attract one another • like charges repel one another.
2. The force between charges varies as the inverse square of the distance, and directly with the charges. (Coulomb’s Law) 3. Charge is conserved. 4. Charge is quantized. (quantized means small discrete packets that can not be further subdivided. For example, you can have 1 or 2 electrons, but never 1. 5 electrons)
The basic unit of positive charge is the proton. (Although protons are ultimately made up of quarks) The basic unit of negative charge is the electron. It is almost always electrons that are moving when charge “flows” The SI unit of charge is the Coulomb ( C). Charge of 1 e- = 1 proton = 1. 6 x 10 -19 Coulombs
Picture Time:
Q
Lisa rubs a piece of fur on glass rod, giving the rod a negative charge. What is the most likely thing that happens? 1) Protons are removed from the rod 2) Electrons are added to the rod 3) The fur is also charged negatively 4) The fur is left neutral
Lisa rubs a piece of fur on glass rod, giving the rod a negative charge. What is the most likely thing that happens? 1) Protons are removed from the rod 2) Electrons are added to the rod 3) The fur is also charged negatively 4) The fur is left neutral
Conductors & Insulators Conductors are materials in which charges are free to move. Metals are a good example. Insulators are materials in which charges can not move. Glass, plastics, and wood, are examples. Q
Which of the following best characterizes electrical conductors? 1) Low mass density 2) High tensile strength 2) 3) Poor heat conductors 3) 5) All of the above 4) charges move freely
Which of the following best characterizes electrical conductors? 1) Low mass density 2) High tensile strength 2) 3) Poor heat conductors 3) 5) All of the above 4) charges move freely
Consider the “pith” ball… - +- -+ + ++ +- Charges are balanced, so the ball is neutral
Consider the “pith” ball… - -- - + + + -
Consider the “pith” ball… - -- - - + - ++ -- +
Consider the electroscope
Consider the electroscope + ++
Consider the electroscope + ++ ++ + + + Explain what happens in pictures & words Charging by conduction—A physical transfer of charge
Consider the electroscope + + + Be ready to explain what happens in pictures & words Charging by Induction
Consider the electroscope + + ++ + + + -- - -- + ++ + + Charging by Induction Still neutral
Consider the electroscope + + ++ + + + -- - -- + ++ + + Charging by Induction
Consider the electroscope + + ++ + + + -- - -- These charges flow from the ground to the electroscope. - - + + + - - ++ + + Charging by Induction These charges remain held in place
Consider the electroscope + + ++ + + + -- - -- The electroscope is now charged. - - - Charging by Induction - Explain what happens in pictures & words These charges now spread out.
Q
An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be… 1) Negative 2) Positive 3) Neutral 5) Depends on the materials. 4) Attracted
An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be… 1) Negative 2) Positive 3) Neutral 5) Depends on the materials. 4) Attracted
An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be… 1) Negative 2) Positive 3) Neutral 5) Depends on the materials. + + ++ +++ - - -- + ++ + + 4) Attracted
- Story behind this picture
- Gravity for dummies and dummies for gravity equations
- Gravity force
- Is air resistance a contact or noncontact force
- How much is the force of gravity
- What is the only force acting on a projectile
- What two factors affect gravity
- Non contact force
- Gravitational force
- Why is gravity a non contact force
- Type of force applied
- A force that opposes motion of a projectile
- Is gravity invisible
- Khi nào hổ con có thể sống độc lập
- điện thế nghỉ
- Thế nào là sự mỏi cơ
- Trời xanh đây là của chúng ta thể thơ
- Gấu đi như thế nào
- Thiếu nhi thế giới liên hoan
- Phối cảnh
- Một số thể thơ truyền thống
- Các châu lục và đại dương trên thế giới
- Thế nào là hệ số cao nhất
- Hệ hô hấp
- Tư thế ngồi viết
- Số nguyên tố là gì
- Hát kết hợp bộ gõ cơ thể
- đặc điểm cơ thể của người tối cổ
- Mật thư anh em như thể tay chân
- Tư thế worm breton
- ưu thế lai là gì
- Thẻ vin
- Cái miệng bé xinh thế chỉ nói điều hay thôi
- Thể thơ truyền thống
- Các châu lục và đại dương trên thế giới
- Từ ngữ thể hiện lòng nhân hậu
- Bổ thể
- Tư thế ngồi viết
- Diễn thế sinh thái là