1. 02/05/2019
Speeding Up
W Richards
Worthing High School

2. Distance, Speed and Time
02/05/2019
Distance, Speed and Time D T S
Speed = distance (in metres)
time (in seconds)
Dave walks 200 metres in 40 seconds. What is his speed?
Laura covers 2km in 1,000 seconds. What is her speed?
How long would it take to run 100 metres if you run at 10m/s?
Steve travels at 50m/s for 20s. How far does he go?
Susan drives her car at 85mph (about 40m/s). How long does it take her to drive 20km?

3. Balanced and unbalanced forces
02/05/2019
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
02/05/2019
Reaction
What would happen if we took the road away?
Weight

5. Balanced and unbalanced forces
02/05/2019
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
02/05/2019
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
02/05/2019
1) This animal is either ________ or moving with _____ _____…
2) This animal is getting _________…
3) This animal is getting _______….
4) This animal is…

8. Balanced and unbalanced forces
02/05/2019

9. Facts on Air Resistance
02/05/2019
Air Resistance is the force that acts ___________ anything that moves through the ______:
It gets _______ when you move faster:
It can be reduced by using a more “__________” (aerodynamic) shape:
Streamlining also works when travelling through _______:
Words – water, air, larger, against, streamlined

10. Words – increase, small, constant, balance
Terminal Velocity
02/05/2019
Consider a skydiver:
At the start of his jump the air resistance is _______ so he _______ downwards.
2) As his speed increases his air resistance will _______
3) Eventually the air resistance will be big enough to _______ the skydiver’s weight. At this point the forces are balanced so his speed becomes ________ - this is called TERMINAL VELOCITY
Words – increase, small, constant, balance

11. Words – slowing down, decrease, increases, terminal velocity, weight
02/05/2019
Consider a skydiver:
4) When he opens his parachute the air resistance suddenly ________, causing him to start _____ ____.
5) Because he is slowing down his air resistance will _______ again until it balances his _________. The skydiver has now reached a new, lower ________ _______.
Words – slowing down, decrease, increases, terminal velocity, weight

12. Velocity-time graph for terminal velocity…
02/05/2019
Parachute opens – diver slows down
Velocity
Speed increases…
Terminal velocity reached…
On the Moon
Diver hits the ground
New, lower terminal velocity reached
Time