Flashcards in Topic 1- Motion, Forces And Conservation Of Energy Deck (49):
8 Energy stores
Kinetic, Thermal, Chemical, Nuclear, Magnetic, Electrostatic, Elastic Potential, GPE
Kenton energy depends on...
Mass and speed
Greater the mass and the faster it’s going, the more kinetic energy
If you double the mass, the energy in the kinetic energy store...
If you double the speed, the energy in the kinetic energy store...
Energy can be ... , ... between stores and ...
But can never be ... or ...
The total energy of a closed system has...
Stored, transferred and dissipated
Can never be created or destroyed
No net charge
Energy can be transferred between stores in four main ways...
A ball rolling up a slope
The ball does work against the gravitational force
So energy is transferred mechanically from the mentor energy store of the ball to its gravitational potential energy store
A bat hitting a ball
Bat has energy in its kinetic energy store
Some out this is transferred mechanically to the balls kinetic energy store
Some is also transferred mechanically to the thermal energy stores of the bat, ball and surroundings
The rest is carried away by sound
Energy is only useful when...
It is transferred from one store to a useful store
Input energy is always ... and ... to the surroundings
Dissipated or wasted
Often to thermal energy stores
When work is done mechanically ... have to be overcome eg.
Frictional forces eg. Things rubbing together and air resistance
Therefore energy needed to overcome this is transferred to thermal energy stores (not useful energy)
What reduces unwanted energy transfers
Lubricants- reduce friction between objects when they move usually liquids like oil, can flow easily between objects and coat them
Insulation- between walls of houses, lowest conductivity means slowest rate of energy transferred through them (thick walls and a air gap between the two walls)
Non renewable advantages
Reliable- can meet the current demand, use more fuel to release more energy
Cheap to build and run fossil fuel power plants
Low cost of extracting fossil fuels
Disadvantages of non renewable
Nuclear power plants cost a lot to build and cause safety issues
Slowly running out
Environmental problems, contribute to global warming
Cause acid rain
Nuclear waste is dangerous
Never run out
Not as much impact on environment
Disadvantages of renewable
Don’t provide much energy
Made from plants and waste
Can not respond to immediate energy demands
Increases methane and carbon dioxide emissions
Reliable because crops grow quickly
Initial costs are high but minimal to run
Lots of them are needed to produce lots of power
Spoil the view
Only work when wind so can’t always supply to high demand
Initial costs are high but minimal to run
Generate small scale electricity
Most suitable for sunny countries
No power made at night
Can’t increase production when there is extra demand
Big impact on environment due to flooding possible loss of housings or habitats
Immediately respond to increased electricity demand
Initial costs are high but minimal running cost
Effect boat access
Can spoil view
Don’t work when water levels are equal both sides
Initial costs are high but minimal running costs
No fuel costs
Have a magnitude (size) and direction
Only have a magnitude and no direction
Just how fast something is travelling with no regard to direction
Velocity is ...
Speed in a given direction
How far an object has moved
Displacement is ...
A measurement of direction and distance in a straight line from a starting point to its finishing point
Acceleration is ...
The change in velocity in a certain amount of time
Deceleration is ...
Constant acceleration can also be called
Example of uniform acceleration
Acceleration due to gravity
a = (v-u) / t
Uniform acceleration equation
(v)2 - (u)2 = 2 x a x X
The 2s around the brackets = squared
The small x = multiply
Large X = distance
Distance- speed graph :
What does the gradient mean
Gradient at any point gives the speed
Flat sections is where the object has stopped
Curves are represent acceleration, the steeper the curve the greater the acceleration and if the curve sloops off the slower the acceleration
Finding speed from a distance - time graph
The gradient = speed
Velocity- time graphs :
Gradient = acceleration
Flat sections = steady speed
Up = acceleration
Down = deceleration
Curve = changing acceleration
How to get distance from a velocity- time graph
The area underneath the graph is the distance travelled
Momentum is ...
A property that all moving objects have. Defined as a product of an objects mass and velocity
Vector quantity - has size and direction
Greater mass or velocity
Affect on momentum
Total momentum before = ?
Total momentum after
What is conservative of momentum
The momentum being the same before and after an event
Newton’s first law
If the resultant force of a stationary object is zero, the object will remain stationary.
If the resultant force on a moving object is zero, it’ll just carry on moving at the same velocity.
A non zero resultant force will ...
Always produce acceleration or deceleration in the direction of the force
Acceleration is proportional to...
Therefore the more an object accelerates the larger the resultant force
Newton’s second law
Resultant force = mass x acceleration
Acceleration is inversely proportional to...
The mass of the object
Therefore the larger the mass, the slower the acceleration