P1 conservation of energy and power Flashcards
What is the law of conservation of energy?
Energy cannot be created or destroyed, only transformed from one form to another.
True or False: Energy can be created from nothing.
False
Fill in the blank: The total energy in a closed system remains _____ over time.
constant
What is kinetic energy?
The energy an object has due to its motion.
What formula is used to calculate kinetic energy?
KE = 0.5 * m * v^2, where m is mass and v is velocity.
What is potential energy?
The energy stored in an object due to its position or state.
What is the formula for gravitational potential energy?
PE = m * g * h, where m is mass, g is the gravitational field strength, and h is height.
True or False: An object at rest has kinetic energy.
False
What happens to energy during a chemical reaction?
Energy is either absorbed or released.
What is power in terms of energy?
The rate at which energy is transferred or converted.
How is power calculated?
Power = Energy transferred / Time taken.
What is the SI unit of power?
Watt (W)
Fill in the blank: 1 Watt is equivalent to _____ Joules per second.
1
What is the relationship between energy and power?
Power is the rate of energy transfer.
True or False: A more powerful machine uses energy more efficiently.
False
What is the principle of energy efficiency?
The ratio of useful energy output to total energy input.
What percentage of energy efficiency is considered good for a machine?
Above 70%
Fill in the blank: Renewable energy sources are considered _____ because they can be replenished naturally.
sustainable
List two examples of renewable energy sources.
Solar energy and wind energy.
What is mechanical energy?
The sum of kinetic and potential energy in an object.
What is the principle of conservation of mechanical energy?
In the absence of non-conservative forces, the total mechanical energy remains constant.
What happens to energy in a closed system during an energy transfer?
Energy is conserved but may change forms.
True or False: Energy transformations always result in some energy being lost as heat.
True
What is thermal energy?
The energy that comes from the temperature of matter.
