Coulomb Force (Static)

1.

a. Observe the arrows representing the Coulomb force between the charges. Do you think this represents an attractive or repulsive force?

The arrows represent repulsive force since they are not facing each other.

b. Change the charge of particle A (q_A) to -10.0 What effect does this have on the arrows? Is this an attractive or repulsive force?

This affected the arrows because now the charges are not the same which make it an attractive force.

c. Change the charge of particle B to -10.0. What kind of force is experienced by two negative charges? You can model this by rubbing two balloons and slowly bringing them together.

A repulsive force is experienced because both charges are the same.

d. Change the charge of particle A back to +10.0. As a rule, what kind of force will result when charges are opposite? What kind of force will result when the particles have the same charge?

When one force is negative and the other one is positive an attractive force is caused.

2.

Change the charge of particle A to 0.0. A particle with zero charge is neutral.

a.       What happens to the force arrows?

The force arrows are gone and it turned into neutral.

b.      What is the force between a charged particle and a neutral particle?

The difference is that there is no attraction or repulsion between them.

 3.

a. What is the Coulomb force on particle A?

10N

b. What is the force on particle B?

10N

c. Drag the particles around. Are the forces on particle A and B always equal to one another?

Yes, they are always equal.

4.

What do you think the force will be if one of the charges is halved?

The force will stay the same on both sides and it will be divided by two.

a. What is the force on the particles now? Does this agree with your hypothesis?

The force now is five, it does agree with my hypothesis since it was 10N and now it is 5N

b. Change the charge of particle B to 5.0 • 10⁻⁴ C. What is the force now?

No, it divided by two and became 2.5N

c. Try several other combinations of charges. (Stick with whole numbers so it is easier to see the relationship.) What pattern do you see?

The numbers are divided in half.

d. Based on your observations, write an equation for Coulomb force when the distance is 30 m. If possible, compare and discuss your equation with your classmates.

D=30 q_a=a, q_b= b N=a,b/2

Static electricity Examples

What is Static Electricity:

Static electricity is an electric charge that has built-up on an object.It is often created when two objects that are poor electrical conductors are rubbed together. The electrons of one object rub of onto another.


Static electricity Examples:


Picture 1:


In this picture a balloon is rubbed to a persons hair and in this case static electricity is caused which is why the child's hair went up towards the balloon and this is caused by the building of electrical charges since the hair and the balloon are poor conductors. 


















Picture 2:


This picture shows a person being shocked by a doorknob with a cause of static electricity. this is caused by the person and it is a small spark that can  jump from your finger to some metal object, giving you a slight shock. this type of shock is the most common one that people experience.














Picture 3: 

  
This picture shows lightning which is the largest spark of static electricity. A lightning bolt can be over 1.5 km or about 1 mile in length. The amount of voltage released in a lightning bolt is typically about 100,000,000 volts, which makes us see it.

Uses and Examples of Static Electricity

Static electricity:(Brainpop)



Receiving an electric shock from a doorknob is an example of static electricity. Static electricity is a cause of an imbalance of positive and negative charges. It is built up when electrons are pulled from one surface to another. Adhesion is the force that causes electrons to move between surfaces. An atom has neutral charges when it has an equal number of protons and electrons. Rubber is a type of insulator, while gold is a conductor. Electrons have a negative charge, and protons have a positive charge. Static electricity is best described as a one-time shock of electricity, like the electricity from a lightning bolt.

Uses of static electricity:

                

              When you take off your wool hat, it rubs against your hair. Electrons travel from your hair to the hat. A static charge constructs. Things with the same charge repel each other. So the hairs try to get as far from each other as possible. The farthest they can get is by standing on end. This is how static electricity causes a bad hair day!

                Static electricity is an electric charge that has built up on an object. It is often created when two objects that are poor electrical conductors are rubbed together. The electrons of one object rub of onto another object.

                We need static electricity to use electrical static precipitators to remove all the dust that comes out of a power station furnaces-instead of it all belching out into the air.

                Some problems that are caused by static electricity are, Air rushing past a car will drag negative charges off the car body and leave it with an overall positive charge. This sounds pretty harmless until you go out and touch the car. That’s when all the static charge suddenly flows through the end of your finger.

Examples of uses of static electricity:

Static Charges give a great paint job, the car body is given a negative charge – the paint is given a positive charge. Now because like charges repel, the positively charged paint droplets all repel each other and so they spread out really well. And because opposite attract – the paint droplets are attracted to the body.

        Some insulating materials become electrically charged when they are rubbed    together. Charges that are the same repel, while unlike charges magnetize.              Electrostatic precipitators, photocopiers and laser printers make useful use of              electrostatic charges.

The Van de Graaff Generator:

        Van de Graaff generator is a device designed to create static electricity and make it available for experimentation. The American physicist Robert Jemison Van de Graaff invented the Van de Graaff generator in 1931. The device that stands his name is able to produce extremely high voltages -- as high as 20 million volts.

 "Physics4Kids.com: Electricity & Magnetism: Introduction." Rader's PHYSICS 4 KIDS.COM. Web. 23 May 2010. .

Body Building! Muscles

Questions:

1. Do Muscles pull or push?
Muscles only pull.

2. What happens when one muscle of the pair contracts (shortens)?
When one muscle of the pair contracts the other one relaxes.

3. In what ways is the model accurate?
It shows how muscles are located in your body specifically and it also shows how muscles contract and relax.

4. In what ways is the model inaccurate?
It is inaccurate because in real life muscles contract but the rubberband only gets shorter.