## S4: work done, potential and kinetic energy

We finished the transport section with a look at Work, Potential & Kinetic energy.  Those of you aiming for Credit need to carry out calculations involving kinetic energy using

$E_k = \displaystyle {1 \over 2}mv^2$

Here is a video about work, potential energy & kinetic energy from Bozeman Science

Most of the calculations will be based on the principle of conservation of energy.  Dr. Altman has an excellent series of videos examining conservation of energy  examples from Roadrunner cartoons.

I have attached a pdf handout with worked examples on potential energy, work and kinetic energy.  If you want some more revision materials, try here.

## balanced and unbalanced forces

Here are some videos on balanced and unbalanced forces affecting the motion of objects.  The first clip examines the forces on a cyclist as she cycles round a velodrome.

The second clip looks at the way skydivers use forces to land safely.

I’ve also attached a pdf with some notes on forces, free body diagrams and Newton’s laws of motion.  Download the file using the link below.

## S4 forces and seatbelts

We’ve been learning about forces in class and today we looked at how car seatbelts use forces to keep us safe.  Mr Mallon’s HelpMyPhysics site has a short video that demonstrates how a monkey can stay safe during a trolley collision when it is given a seatbelt.

Here is a seatbelt advert from Sussex, the family’s arms show what a seatbelt does.

The next youtube seatbelt advert is pretty graphic – it’s designed to show what happens to our insides when we travel without a seatbelt.  Here is a link to the video, please don’t click if you’re squeamish.

There are several pages of notes about forces on BBC Bitesize.  Remember to try their test when you have worked through the topic.

I have attached a pdf from RoSPA that provides a history of the car seatbelt.  Ignore the bad man who was the face of seatbelt campaigning in the 1970s…

## booklets for all standard grade physics units

I’ve been asked to post a link to all of the booklets so that people have access to something like the energy booklet as they revise using electricity and electronics.  I’ve added these to the standard grade page now.  Look for a link called whole unit notes in each section.

For those of you who have yet to download a copy of the SQA Physics booklet, get yours here.

Ria asked if a slinky really stops in mid air when it is released.  Eoin helped us to find out the answer.

It’s easier to see what happens if you watch a slow motion version.

Or even slower motion.

Why does that happen?

## measuring reaction time

We measured people’s reaction time in class today using this BBC site.  Click on the picture to try again at home.

It is important to consider reactions when we measure short times.  In Physics, we often try to avoid reaction times affecting our results by using data loggers and light gates to take accurate time measurements.

Read about using light gates to measure average speed and instantaneous speed on pages 6 & 8 of your Transport booklets.

## snow day work for S4

If you can’t get to school due to the weather, here is some work for you to do at home.  We will start the Transport topic when we have finished our Investigations.  Please use these notes to begin looking at the Transport unit.

Read the notes on average and instantaneous speed and try the questions.  If you have a printer at home, please also try to print out the pages with squared sections to practice drawing speed-time graphs.

## S4 transport HW

Here is your HW exercise on the speed & acceleration work we have just covered in class.  Please hand your HW jotter in no later than Friday 4th December.

## Free physics software

I’ve had an email from Yenka to say that they are now offering many of their products for home use – free of charge!  I think Yenka is the new name for Crocodile Clips, the company who made Crocodile Physics and Crocodile Technology.  Their software allows you to create your own experiments to learn about

• motion – SG transport, Int2 unit1, Higher unit1, AH unit1
• electricity – SG using electricity, Int2 unit1, Higher unit2, AH unit2
• light and sound – SG health physics, Int2 unit3, Higher unit3, AH unit3
• electronics – Int1 applied practical electronics, SG electronics, Int2 unit2, Higher unit2

They also have some chemistry products you might find helpful.

The software is free but you can only use it at home.  Why not download it and see if you find it useful.

## S4 Transport – extra notes about forces and energy

We’ve completed the unit of Transport now. I have uploaded the summary notes we went through on forces, work, power and energy. I’ve also made up 2 sets of notes to show you how to work your way through different types of problems based on potential and kinetic energy. All of the documents are pdf files.

forces

work, power and energy

kinetic energy examples