Helpmyphysics

Hi physics lovers. Check these two videos below on internal resistance.

How to calculate the internal resistance of a cell.

Investigating the internal resistance of a cell.

A couple of months ago my higher physics class performed the famous egg experiment.

Could an egg be thrown at something without breaking?

Our physics tells us that to bring something to a stop its momentum must be reduced to zero.
Now there are 2 possibilities:

1. The egg`s momentum could be reduced to zero over a very short time resulting in the need for a LARGE force to be applied to the egg.
2. Or. The egg`s momentum could be reduced to zero over a longer time resulting in the need for a smaller force to be applied to the egg.

In our movie we throw the egg at a bed sheet and at a solid wooden board.
In both cases the size of the momentum is nearly the same.

So we have this equation:

impulse = change of momentum
Ft = mv – mu.
So if the egg `s momentum is brought to zero over a longish time then the force required to stop it would be small, thus the force to stop the egg wouldn`t damage it!

Could a bedsheet prove this?

You judge.

Click on the link here to take you to the PhET circuit builder.
Use the worksheet below to carry out the practical.

internalresistancePhET

Hi Physics lovers over the next few weeks and after Christmas we will be studying electric circuits.
Those brilliant people from PhET have a brilliant virtual circuit builder.

You can download it here and run it on your pc or laptop. You don`t need to be online to use it after it is downloaded.

I will be adding worksheets to build circuits.

Click to Run

As a starter activity build the following circuit.

3 lamps: Change their resistances as shown: 6 ohms, 2 ohms and 1 ohm by right clicking the lamps
2 cells each having a value of 9V
Use non-contact ammeter
also use a voltmeter.

Measure the pd across the cell = 18 volts.
Now measure the pd across each lamp to see if they add up to the cell`s pd.

It is the biggest story in the world of physics. Here is a good infographic to read and impress your science/physics teacher with.

Source:LiveScience

My Higher Physics students explored electric fields today.
Most important fact is that an electric field is a region in space where charged particles like electrons or protons experience a force.
The Electric field can be visualised with arrows. The direction of which tells you the direction a small positive charged particle would experience the electric force.
Try this fascinating PhET Simulation called Electric field hockey.

Click to Run

Electric Hockey

A super time lapse film of the International Space Station as it flies over the planet.
Look out for the aurora. These are the green bands on the edge of the Earth. You can also see lightning storms and big cities lit up at night.
What a joy to see.

Earth | Time Lapse View from Space, Fly Over | NASA, ISS from Michael König on Vimeo.

Hi physics lovers. Check my video of the swinging mass. See! I trust in my physics and I`ve still got my teeth.