Name 3 things that forces can do to an object Questions Name 3 things that forces can do to an object What is the difference between contact and non-contact forces? Classify the list of forces we generated earlier as contact or non-contact

On your diagram, place the four arrows in the correct place around the car and match with the appropriate label How would it change if the car was: Accelerating Slowing down Stationary?

There are forces on us all the time True or False… Which of these ideas about forces are true and which are false? There are forces on us all the time I’m not moving so there are no forces on me Wood will float and metal will sink Anything with air in it will float Magnetism is a contact force as magnets can touch each other

Use the newton meters to investigate the forces needed to: Open a cupboard door Lift up your pencil case Lift a weight of 100 grams Lift a weight of 200 grams Write your results in your notes…what do you notice about the results for the last two measurements?

Astronauts can experience ‘weightlessness’ Astronauts can experience ‘weightlessness’. They still have the same mass, as they still have the same atoms that make up their bodies. But why have they no weight in space?

Person Mass Weight on Earth (G = 10) Weight on Moon (G = 1.7) Weight on Mars (G = 3.8) Weight on Jupiter (G = 25.4) Weight on Pluto (G = 0.6) Mr Griffiths

Look at these images. Do they show situations where friction is being increased or reduced? How? Why?

Starter A man tries to push this chest of drawers across the carpet. He cannot get it to move. Explain in terms of forces what is happening…ensure you use the words gravity, friction and force in your answer.

Questions: 1. What forces are present on planes when they fly/ 2. Which designs work best? 3. Explain your answer to question 2 using ideas about forces 4. What did you need to keep the same in each experiment? 5. Did your changes improve the distance the planes flew? Why or why not?

Why is this car shaped like this?

Air Resistance - This question was asked in a test What is air resistance? 3 people gave 3 different answers. Decide who was right and write their answer down Sarah wrote: Air resistance is when air stops objects from moving Michael wrote: Air resistance slows objects down. It is caused by air particles hitting moving objects Dan wrote : Air resistance is when air helps cars to move

What is water resistance? Water resistance is similar to air resistance but acts in water. It is caused by water particles hitting moving objects Answer the question What is water resistance? With a similar answer to the correct answer to the last question

Streamlining Objects that move through air or water can reduce drag by being streamlined. This means that they can cut through the air or water easily. The train on the right is more streamlined than the one on the left, helping it to move faster through the air

Streamlining – answer these questions in full sentences What does streamlining aim to reduce? How does it do this? 3. Which of these objects is the most streamlined? Which one do you think can go the fastest? Concorde Cargo plane

Which of these objects are streamlined and which aren’t? Streamlining Which of these objects are streamlined and which aren’t? Man running Jellyfish Olympic cyclist Dolphin

Drag helps objects to move faster True or False – decide whether these statements are true or false – write down the true ones Drag helps objects to move faster Streamlining helps objects to move faster by minimising drag 2 forms of drag are air and water resistance Streamlined objects don’t cut through air or water more easily

What is the normal or ‘contact’ force? What two things does friction depend upon? Why does it take more effort to push a car across a road than a bike? Why can you pull an ice-skater across ice more easily than you can pull a person across grass? In the diagrams below, indicate the direction of the normal contact force

Investigating how the size of the normal ‘contact’ force and the nature of the surface affect friction Newton meter cable Plank with weights You can: Change the size of the weights on the plank. This increases or decreases the size of the normal contact force Change the surface on the desk. By pulling on the newton meter you have to overcome friction in order to make the plank move. The size of the force on the newton meter therefore reflects the size of the friction. Plan: In your groups, write a plan for the experiment. Make sure you: a) Write a step-by-step plan of what you will do b) Decide what weights you will use c) Decide how many times each measurement will be repeated d) Draw a table for your results e) Say what you will keep the sale each time f) Say what you will change each time Remember…your plan needs to explain how you will investigate both the surface and the size of the normal ‘contact’ force

Results and Conclusions How did increasing the size of the normal ‘contact’ force affect friction? How do you know? How did changing the surface affect friction? Why do you think some surfaces have greater friction than others? Draw a graph to represent your results How do you think the experiment could have been improved? Do you think your results are reliable (is there a lot of variation between results or are they similar for one weight or surface) Can you draw a conclusion? Is there a clear trend? Are there any anomalous results?

Exploring Magnetism After completing each mini-experiment, remember to record your results properly Suspend a bar magnet in a piece of paper as I have shown you. Using another bar magnet, move it towards the suspended one. What happens when two of the same poles come close? What happens when two different poles come close? Using a bar magnet, try to pick up some of the following materials. Record which ones are magnetic Copper Iron Plastic Paper Wood Take a bar magnet and the petri dish containing the iron filings Move the iron magnet close to the iron filings in the dish What do you see? Why do you think the iron filings have to be kept in the dish? Take a bar magnet and place it on top of the mini-compasses Draw what you see Why do you think this happens? Take a compass and a bar magnet Where does the compass point when away from the magnet? What about when close?

Answer these questions in full sentences Magnetism Answer these questions in full sentences Define the words attract and repel? What is a permanent magnet? 3. Give an example of a permanent magnet? 4. What 3 materials are magnetic? 5. What is an electromagnet? 6. How is an electromagnet different from a permanent magnet? 7. How can you increase the strength of an electromagnet?

Which object is elastic and which isn’t? What might object 1 be? Draw line graphs to represent the lengths of two objects as forces are applied and then removed over a 10 second period Use a full piece of graph paper and do both line graphs on the same axes Time (s) Object 1 length (cm) Object 2 length (cm) 12 7 1 15 9 2 18 11 3 21 13 4 24 5 27 17 6 16 8 10 Length Time Which object is elastic and which isn’t? What might object 1 be?