Easter Revision Summary Sheets Paper One Flashcards
What is a system
An object or group of objects
Describe energy store changes for a football that has been kicked upwards
As the ball move upwards the kinetic energy store off the ball decreases and the gravitational potential energy store of the ball increases
Describe the energy store changes for a squash ball hitting the wall
When the ball hits the wall, the kinetic energy store of the ball decreases and the elastic potential energy energy store increases. Some energy is transferred to surroundings. The thermal energy store of the surroundings also increases.
Describe the energy changes for a car accelerating
As the car moves, the chemical energy store of the petrol decreases and the kinetic energy store of the car increases. Some energy is also transferred by sound waves to the surroundings and the thermal energy store of the surroundings also increases
Describe energy store change for a car deacclerating
As the car slows down, the kinetic energy store decreases and the thermal energy store of the surroundings and brakes increase. Some of the energy is also transferred by sound waves to surroundings
Describe energy store changes for bringing water to boil
Energy is transferred electrically from the chemical energy store in the power station to the heating element in the kettle and the thermal energy store of the water increases, which increases the kinetic energy store of the particles that make up the water
What is the unit for kinetic energy, mass, speed
Joules, J
Kilograms, kg
Metres per second, m/s
What are two examples of objects with kinetic energy stores
Toy car travelling down the ramp
Gas particles moving in the air
What are the units for elastic potential energy, spring constant and extension
Joules, J
Newtons per metres, N/m
Metre, m
What are two examples of objects with elastic potential energy stores
Stretched elastic band, extended spring
What are the units for gravitational potential energy, mass, gravitational field strength and height
Joules, J
Kilograms, kg
Newtons per kilogram, N/kg
Height, m
What are two examples of objects that have gravitational potential energy stores
Apple on a tree
Aeroplane in sky
What are the units for change in thermal energy, specific heat capacity
Joules, J
Joules per kilogram, J/kg
What is the definition of specific heat capacity
The amount of energy needed to increase the temperature of a 1kg material by 1oc
Define power
The rate of doing work
What are the unis for power, energy transferred, time and work done
Watts, W
Joules, J
Seconds, s
Joules, J
An LED bulb has a power rating of 8W, a halogen bulb has a power rating of 28W but they both have similar brightness. What is the difference?
The LED bulb transfers less energy per second than the halogen bulb
The power output of a hairdryer is 2000W. How much energy is transferred per second?
2,000 joules per second
What is the law of conservation of energy
Energy cannot be created or destroyed. It can be transferred, stored or dissipated
Define dissipation
Energy being transferred to surroundings
How does thermal conductivity of a material affect how it transfers energy by conduction
If a material has a high thermal conductivity, it will transfer heat via conduction at a much quicker rate
How is energy lost from a building? What factors affect this?
Energy is transferred to thermal energy stores of the surroundings. The factors that affect this are the thermal conductivity of the walls and their thickness
