1. Forces and their effects
11/11/2018
Forces and their effects
W Richards
Worthing High School
Please note – some of the animation effects used here only work in PP XP

2. Words – upthrust, air resistance, friction, weight
What is a force?
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A force is a “push” or a “pull”. Some common examples:
___ ________ (drag) – acts against anything moving through air
________ – pulls things downwards
_____ – acts against anything moving
______ – keeps things afloat
Words – upthrust, air resistance, friction, weight

3. Balanced and unbalanced forces
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Reaction
Consider a camel standing on a road. What forces are acting on it?
These two forces would be equal – we say that they are BALANCED. The camel doesn’t move anywhere.
Weight

4. Balanced and unbalanced forces
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Reaction
What would happen if we took the road away?
Weight

5. Balanced and unbalanced forces
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What would happen if we took the road away?
The camel’s weight is no longer balanced by anything, so the camel falls downwards…
Weight

6. Balanced and unbalanced forces
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What would happen if we took the road away?
The camel’s weight is no longer balanced by anything, so the camel falls downwards…

7. Balanced and unbalanced forces
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1) This animal is either ________ or moving with _______ _____…
2) This animal is getting ________…
3) This animal is getting _______….
4) This animal is also either _______ or moving with ________ ______..
Words - Stationary, faster, slower or constant speed?

8. Weight and Mass
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The MASS of an object is a measure of how much “stuff” it contains”.
The WEIGHT of an object is the amount of force that pulls it downwards due to gravity.
1 Kg
This object has a MASS of 1Kg…
…and a WEIGHT of 10N

9. Floating
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Whether or not an object will float depends on its DENSITY. For example:
The metal block will ____ because it is ______ dense than water
The wooden block will ____ because it is ______ dense than water

10. Friction What is friction? Give 3 examples where it is annoying:
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What is friction?
Give 3 examples where it is annoying:
Give 3 examples where it is useful:
What effect does friction have on the surfaces?

11. Stopping a car… Tiredness Too much alcohol Thinking distance
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Tiredness
Too much alcohol
Thinking distance
Too many drugs
Poor visibility
Wet roads
Icy roads
Braking distance
Tyres/brakes worn out
Driving too fast

12. Distance-time graphs 2) Horizontal line = 40 30 20 10
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2) Horizontal line = 40 30 20 10
4) Diagonal line downwards =
Distance
(metres)
3) Steeper diagonal line =
Time/s
Diagonal line =

13. 40 30 20 10 20 40 60 80 100 Distance (metres) Time/s
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Distance
(metres)
Time/s
How far had the object gone after 20 seconds?
How far had the object gone after 60 seconds?
When is the object standing still?
When was the object travelling the fastest?