Energy transfer Flashcards
How hair dryer and a washing machine transfer electrical energy into kinetic and thermal energy and why?
The electric energy is transferred into kinetic energy to power the motors and suck the air through the hair dryer and the thermal energy heats the air. A washing machine needs kinetic energy to move the drum and washes the clothes and uses thermal energy to heat the water.
What is power measured in?
Watts and Joules
How many Joules is 1 watt per second?
1
What is the definition of work done?
Whenever force is used to move an object
What is the definition of a joule in N/m?
When an object is moved 1m by a force of 1N, 1J of work is done.
What is internal energy?
Internal energy is the amount of energy stored in a system by the particles.
What happens to the internal energy of a substance when you heat it up and cool it down?
When you heat up a substance the internal energy increases and when you cool it down the internal energy decreases.
What happens to the amounbt of particles during changes of state?
Nothing, you dont lose or gain any particles
What is the definition of a specific heat capacity of a substance?
The amount of energy needed to raise 1Kg of a substance’s temperature by 1 degree.
What does latent heat mean?
Latent heat means the energy needed to change a substance’s state
How can you increase the pressure of a gas that’s in a container (in terms or particles)?
You can increase the amount of collisions or the energy of collisions with the walls, you could do this by increasing the temperature.
What is the link between temperature and kinetic energy in terms of particle collisions?
the lower the temperature, the lower the energy and the amount of collision/ lower temperature.
What is the specific latent heat of fusion of a substance?
The amount of energy required to change 1Kg of substance from solid to liquid with no change in temperature.
What is specific latent heat of vaporization?
The amount of energy needed to change 1Kg of a substance from a liquid to a vapour with no change in temperature.
what energy store does a stretched string have?
Elastic Potential Energy
What is extension measured in
meters
What is a specific heat capacity of an object?
The amount of energy required to raise 1kg of substance by 1 degree celsius
What is thermal energy?
The energy stored due to an object’s temperature
Whats gravitational potential energy?
The energy stored in an object based on the objects height
What energy transfers as a pendulum swings?
At the highest point it has the most GPE and the least KE, at the lowest point it has the most KE and the least GPE. As the pendulum moves across the air, there is friction between the pendulum and the particles in the air which causes the air and the pendulum to heat which is thermal energy, as more energy is transferred to this less will be transferred to the KE and GPE which leads it to slow down.
What energy transfers happen during a bungee jump?
Before the person jumps they have GPE, once they jump the GPE is transferred into KE and thermal energy (friction) which dissipates. When the jumper reaches full extension they have only EPE and when they begin to ascend they gain more GPE and KE and lose EPE. This cycle continues until the jumper stops and has no KE and only EPE.
What is mechanical force?
using force to move an object
What is electrical work?
When a current transfers energy?
What is power?
The rate at which energy is transferred.
What are the jobs of step up and step down transformers and why do they have these jobs?
Step up transformers increase the potential difference and decrease the resistance, this decreases the energy loss in the transmission cables. The step down transformer then decreases the potential difference to about 230V before its sent into houses, this is because previously the potential difference would be too high to send into UK homes.
What are the jobs of step up and step down transformers and why do they have these jobs?
Step up transformers increase the potential difference and decrease the resistance, this decreases the energy loss in the transmission cables. The step down transformer then decreases the potential difference to about 230V before its sent into houses, this is because previously the potential difference would be too high to send into UK homes.
What is the density of a material?
the amount of mass packed into a certain volume, e.g a brick has a high density and something like a polystyrene block has a low density because it has a low mass packed into a certain volume
Why do solids and liquids normally have a high density?
Because lots of particles are closely packed together, they normally have a higher mass for their volume.
