Transcript P2 Revision

Motion Revision
Circumference = 2πr
Speed = distance / time
If the International Space Station is
350km up (7000km from the Earth's
centre) and orbits in 90 minutes, how
fast is her toolbox travelling?
Distance Time Graphs
► Describe
the motion
of the object during
regions a b c
Velocity and Acceleration
1.
2.
3.
•
•
Velocity and speed are different; one of
them has a direction, but which one?
What is the standard unit for speed?
What is the standard unit for
acceleration?
Acceleration = change in velocity
time taken for change
Velocity Time Graphs
► This
graph shows
the acceleration of a
rocket, how fast is it
accelerating?
Using Graphs
► Calculate
the
distance travelled
by this object
(remember, it’s the
area under the
line).
Speed of Light Questions
► Light
speed = 300,000 km/s
► Light takes the following time to get to:
► The Moon = 1.5 seconds
► The Sun = 8 minutes
► The nearest other star = 4 years
► The nearest galaxy = 2,500,000 years
► Now work out the distances!
Speeding up and
slowing down
Revision
Forces Between Objects Questions
1.
2.
3.
If a boy pushes a shopping trolley with a
force of 100N, what force is exerted on
the boy by the trolley, and in which
direction?
We say that the forces are _________
and _________.
What is a terminal velocity? Give an
example.
Resultant Force Questions
1.
2.
3.
A plane is flying at a steady speed at the same
altitude, draw a diagram of the forces acting on
it, forces represented as arrows.
The plane decelerates and descends, draw
another diagram of the forces acting on it.
In the two above questions, describe the
horizontal and vertical resultant forces.
Force and Acceleration Questions
1.
2.
F=ma; rearrange to find mass and
acceleration.
Copy and complete the table:
Force (N)
(A)
100
20000 50
(E)
Mass (kg)
70
(B)
1000
(D)
200
Acceleration
(m/s2)
10
10
(C)
43
15
On the Road Questions
Stopping Distance
= Thinking Distance + Braking Distance
1.
2.
3.
List the factors that would increase
braking distance.
List the factors that would increase
thinking distance.
List the factors that would decrease
thinking distance.
Earth ~10N/kg
Mars ~4N/kg
Falling Objects
Moon ~1.5N/kg
•
1.
2.
3.
Weight (N) = Mass (kg) x Gravitational
Field Strength (N/kg)
What is the weight of a 60kg person on
Earth/Mars/Moon?
What is the weight of a 5kg cat on
Earth/Mars/Moon?
What is the weight of a 1200kg car on
Earth/Mars/Moon?
Work, Energy and Momentum
Revision
Energy and Work
•
Copy: Work done = Force x Distance
(J)
(N)
(m)
1. How much work is done when a pupil lifts
their 7kg bag onto a desk 1.2m high?
2. How much work does a teacher do when
carrying 15kg of books 80m?
Kinetic Energy
Copy: Kinetic Energy = ½ x Mass x Velocity2
(J)
(kg)
(m/s)
1. A 1.2 ton car travelling at 30m/s has a
Kinetic energy of?
2. A 10kg toolbox travelling at 4km/s has a
kinetic energy of?
Momentum
Copy: momentum = mass x velocity
(kg m/s)
(kg)
(m/s)
1.Calculate the momentum of a 60kg person
running at 5m/s
2.Calculate the momentum of a 80kg person
walking at 2m/s
Collisions and Explosions
In a collision:
momentum before = momentum after
In an explosion, where A and B are ejected:
Momentum of A = -Momentum of B
Or Momentum of A + Momentum of B = 0
Changing Momentum
• Force = Change in momentum
time taken
• Therefore, the more time an impact takes,
the more force is exerted.
• Slowing down an impact makes it safer, for
example: air bags, car crumple zones,
mats in the gym, etc.
Questions
• Turn to page 222 in the books and work
through the green Summary Questions.
Static Electricity Revision
Charge
1. Electrical charge can either be ______ or
_______.
2. Like charges _______.
3. Unlike charges _________.
4. To become _______ a insulator must lose
electrons.
5. To become _______ a insulator must gain
electrons.
Moving Charge
1. Define electrical current.
2. Describe what happens when a charge is
earthed.
Uses of static
• Can you think of 3 uses of static? Discuss
with a partner.
• Can you think of 2 dangers caused by
static? Discuss with a partner.
Current Electricity Revision
Electric Circuits
• Name these circuit
symbols:
• 1
• 2
• 3
• 4
• 5
• 6
•7
•8
•9
• 10
• 11
Resistance
• Resistance (Ω) = Voltage (V)
Current (A)
• The current through a wire is 3A when the
potential difference is 9V, what is the
resistance of the wire?
Current-Potential Difference
Graphs
•
Which graph links to
which component?
1. Resistor at constant
temperature
2. Diode
B
3. Filament Lamp
A
C
Series Circuits
• http://www.bbc.co.uk/schools/gcsebitesize/
science/add_aqa/electricity/circuitsrev5.sht
ml
Parallel Circuits
• http://www.bbc.co.uk/schools/gcsebitesize/
science/add_aqa/electricity/circuitsrev6.sht
ml
Mains Electricity Revision
Alternating Current
1. Alternating current repeatedly reverses
its ___________.
2. A torch battery could have a voltage of
___.
3. A car battery may have a voltage of ___.
4. Mains electricity is ___.
Cables and Plugs
1. Why are the wires made of
metal?
2. Why is the case made of
plastics?
3. Why is there a fuse?
4. Is the fuse in series or
parallel?
5. Why is there an earth wire?
Fuses
1. Why do we use fuses?
2. What happens inside a fuse if too much
current flows?
3. Should the rating of the fuse by slightly
lower, slightly higher or exactly the
current of the appliance?
4. How are circuit breakers different to
fuses?
Electric Power and Potential
Difference
•
•
Power (W) = Current (A) x Voltage (V)
Power (W)= Energy transferred (J)
time (s)
1. A computer transfers 150000J of energy
when used for 5 minutes, what is its
power use?
Electrical Energy and Charge
•
Charge flow (C) = Current (A) x time (s)
•
Energy (J) = Voltage (V) x Charge flow (C)
1. Calculate the charge flow when the energy is
150J and the voltage is 3V
2. Calculate the maximum charge flow when 5A
fused computer is used for 30 minutes.
Nuclear Physics
Revision
Nuclear Reactions
1. Which decay emits an electron?
2. Which decay emits a helium nucleus?
3. Which decay changes the atomic number by
+1?
4. Which decay doesn’t change the mass
number?
5. What symbols represent alpha and beta?
6. What are the 5 main sources of background
radiation?
The Discovery of the Nucleus
1. Where is most of the mass in an atom?
2. What charge does the nucleus have?
3. What charge does an alpha particle
have?
4. {H} Write down bullet points on how the
nucleus was discovered.
Nuclear Fission
1. What isotopes are typically used for
fission?
2. Is a chain reaction wanted or unwanted?
3. What triggers fission of a nucleus?
4. Why are control rods used in reactors?
Nuclear Fusion
1. What happens to 2 nuclei when fusion
occurs?
2. What is plasma?
3. How is the plasma contained in the
fusion reactor?
4. What happens to the nuclei if the plasma
is not hot enough when they approach
each other?