# p2 aqa

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• Created by: bbyjujux
• Created on: 01-05-17 18:18
forces between objects- what can a force change?
A force can change the shape of an object or change its state of rest (stop an object) or its motion (change its velocity)
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what are all forces measured using?
All forces are measured using the unit Newton
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a force is a...
push or a pull
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what happens when two bodies interact?
the forces they exert on each other are equal in size and opposite in direction
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what is there for every action force?
there is an equal and opposite reaction force
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what happens when two objects interact?
the forces they exert on each other are equal and opposite
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what happens to the number of forces acting at a point
they may be replaced by a single force that has the same effect on the motion as the original forces all acting together
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what is the single force called?
resultant force
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what can a result force acting on an object?
can cause a change in its state of rest or motion.
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velocity/time graph part2- what does a horizontal line mean?
object is travelling at a constant velocity
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what does a straight sloping line mean?
the object is accelerating or decelerating.
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the steeper the slope...
the faster the acceleration or deceleration.
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what does a curved line mean?
acceleration is changing.
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what is the area under the graph
The area under the graph is the distance travelled
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what can a acceleration or deceleration of an object be calculated from?
the gradient on a velocity – time graph
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the area underneath a velocity tells you what?
the distance that an object has travelled
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vectors and velocity- what are quantities know as?
Quantities which have a direction and size are known as VECTOR QUANTITIES.
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what are the 4 examples DAVF
Displacement- distance travelled in a particular direction. Velocity – speed in a particular direction. Force – always has a size and direction. Acceleration – it has size and direction
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on the road what = the stopping distance?
thinking distance+ breaking distance
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the total distance needed to stop a car is not just....
the distance the car travels after the brakes have been applied, there is also the time needed for the driver to react to seeing something.
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what is this called?
stopping distance
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what is thinking distance?
is the distance the car travels during the driver’s reaction time seeing something. There are many factors that can affect your reaction time.
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factors affecting thinking distance
Age of driver, Drugs e.g. alcohol, Tiredness, Distractions,Visibility, Speed
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factors affecting breaking distance
Mass of vehicle, Speed of vehicle, Poor maintenance,Poor weather conditions, State of the road, Amount of friction between the tyre and the road surface
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falling objects - weight and mass are not what?
the same thing
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what is weight?
The weight of an object is the force of gravity on it. Weight is measured in Newtons (N)
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what is mass
The mass of an object is the quantity (amount) of matter in it. Mass is measured in Kilograms (Kg)
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what happens in a vacuum?
All falling bodies accelerate at the same rate. In the atmosphere Air resistance increases with increasing speed. Air resistance will increase until it is equal in size to the weight of a falling object
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what happens in a vacuum?
When the two forces are balanced, acceleration is zero and TERMINAL VELOCITY is achieved. An object acted on only by the Earths gravity accelerates at about 10 m/s2
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what happens between a & B
The object accelerates at first because of the force of gravity. The weight of the object is greater that the air resistance forces.
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what happens between B & C
The object is still accelerating but its acceleration decreases as time goes by. This is because frictional force (air resistance) acting against it is increasing as the speed increases.
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what happens between c and d
The object is not accelerating any more. It has reached its terminal velocity and is falling at a steady speed. The resultant force is zero because the frictional force acting against it is now the same as the weight of the object.
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stretching and sqaushing- what does a force applied to an elasticobject such as a spring result in
the object stretching and storing elastic potential energy
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what does hooke law state?
The extension of a spring is directly proportional to the force applied, provided that its limit of proportionality is not exceeded.
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the extension of a...
material is its current length minus it original length.
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hook law?
If you over stretch a spring Hooks law no longer applied and the spring may not return to its original shape.
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when over....
6 Newton has been applied the limit of proportionality has been exceeded!
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energy and work- what is the defenation of work
the amount of energy transferred. Measured in Joules (J
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what is power?
The rate of doing work. Measured in Watts (W). 1 joule per second is 1 watt.
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what happens when a force causes a object to move?
a distance, work is done
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electrical power and energy- what is a current in a wire
a flow of electrons
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what happens when the electrons move in a metal
they collide with the ions in the lattice and transfer some energy to them.
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this is why....
a resistor heats up when a current flows through.
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what are the advantages of the heating effect of an electric current
Useful Heating a kettle, Useful in Fires
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what are the disadvantages of the heating effect of an electric current
Wasted energy, cause burns
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Gravitational potential energy- what does it mean?
The energy that an object has by virtue of its position in a gravitational field
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what happens when an object is moved?
gravitational potential energy increases.
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what happens when an object is moved down?
its gravitational potential energy decreases
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kinetic energy- what happens when an object speeds up or slows down
Its kinetic energy increases or decreases.
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what is a momentum of an object produced by?
the object’s mass and velocity.
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what is elastic potential energy?
the energy stored in an elastic object when work is done) can be transferred into kinetic energy.
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momentum- what is it?
Momentum is a property of moving objects
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what happens in a close system?
the total momentum before an event is equal to the total momentum after the event. This is called conservation of momentum.
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what is conservation of momentum?
The total momentum before an event is equal to the total momentum after the event
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explosions- whentwo objects push each other apart they also
move apart
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with different and equal what?
With different speeds if they have different masses With equal and opposite momentum so their total momentum is zero
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impact forces- When two objects collide the force of the impact depends on....
3 factors
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what a do the factors depend on
The mass of the objects The change in velocity The duration (time)of the impact
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the longer the impacts last......
the greater the impact force is reduced
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what happens when two vehicles collide
They exert equal and opposite forces on each other Their total momentum is unchanged
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what happens when crumples zones designed for?
to lessen the effect of a collision
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what are the forces in a collision
the forces change the momentum of the car
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what happens i head on collisions
the momentum of the car is reduced.
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what happens in rear end collisions
momentum is increased. Crumple zones increase the impact time
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car safety-what happens when you are travelling in a car
you are travelling at the same speed as the car
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what happens when the car stops
your momentum continues to carry you forward
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what happens when you suddenly hitting the dashboard or ground
you experience a large force, and therefore a large amount of damage.
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car safety features- seatbelts
stretch to increase the time taken to stop, thus reducing the rate of change of momentum and reducing injury
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air bags
inflate to increase the time taken to stop, thus reducing the rate of change of momentum and reducing injury
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crumple zones
crumple and fold in a specific way to increase the time taken to stop, thus reducing the rate of change of momentum and reducing injury
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potential and kinetic energy- what does kinetic energy mean
movement energy
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gravitational potential energy
the energy something has due to its position relative to Earth – i.e. its height.
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what conservation of energy
When energy is transferred, the total amount always remains the same.
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what can friction be use for?
to create a static charge
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what happens when an insulator is rubbed with a cloth
it can become charged in 2 ways
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way number 1?
electrons move from the cloth to the insulator, the insulator ends up with an overall negative charged
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way number 2
electrons move from the insulator to the cloth. the insulator ends up with an overall positive charge
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static electricity- 1, what happens when certain insulating materials are rubbed against each other
other they become electrically charged. Negatively charged electrons are rubbed off one material and on to another.
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1.5 what are negatively charged rubbed off?
one material and on to another
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2, what happens to the material that gains electrons
becomes negatively charged
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2.5 what happens to the material that loses electrons?
its left with an equal positive charge
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3 what happens when two electrically charged objects are brought together?
they exert a force on each other
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4.what do two object that carry the same charge do?
repel
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4.5 what do two objects that carry different chargers do
attract
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5. what can electrical charges do?
move easily through some substances
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what does electric current mean?
its a flow of electric charge.
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what is the size of the electric current & what is it measured in?
the rate of electric charge, its measured in amps
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what is the potential difference between two points in an electric circuit?
the work done (energy transferred) per coulomb of charge that passes between the points
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what is the question above measured in?
volts
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what are electric circuits assembled from?
componets
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what does each compound have?
an internationally-agreed symbol
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what does a circuit diagram show?
how components are connected using the standard symbols
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what happens when a componets are connected in a complete circuit?
an electric current flows
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what is the charge carried out by?
a very large number (millions of millions) of electrons, each of which has a negative charge
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what is the unit of current?
the ampere (A) and the unit of charge is the coulomb (C).
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## Other cards in this set

### Card 2

#### Front

what are all forces measured using?

#### Back

All forces are measured using the unit Newton

### Card 3

a force is a...

#### Back ### Card 4

#### Front

what happens when two bodies interact?

#### Back ### Card 5

#### Front

what is there for every action force?

#### Back 