energy. Flashcards
What is energy defined as in physics?
Energy is defined as the capacity to do work.
What are the two main types of energy?
The two main types of energy are kinetic energy and potential energy.
What is kinetic energy?
Kinetic energy is the energy of an object due to its motion.
What is the formula for kinetic energy?
The formula for kinetic energy is KE = 1/2 mv², where m is mass and v is velocity.
What is potential energy?
Potential energy is the energy stored in an object due to its position or configuration.
What is the formula for gravitational potential energy?
The formula for gravitational potential energy is PE = mgh, where m is mass, g is acceleration due to gravity, and h is height.
True or False: Energy can be created or destroyed.
False: Energy cannot be created or destroyed; it can only be transformed from one form to another.
What is the principle of conservation of energy?
The principle of conservation of energy states that the total energy in a closed system remains constant.
What is thermal energy?
Thermal energy is the energy related to the temperature of an object, arising from the kinetic energy of its particles.
What is the unit of energy in the International System of Units (SI)?
The unit of energy in SI is the joule (J).
What is work in terms of physics?
Work is done when a force causes an object to move in the direction of the force.
What is the formula for work done?
The formula for work done is W = Fd cos(θ), where W is work, F is force, d is distance, and θ is the angle between the force and the direction of motion.
What is mechanical energy?
Mechanical energy is the sum of kinetic and potential energy in a system.
What is the difference between elastic potential energy and gravitational potential energy?
Elastic potential energy is stored in objects that can be stretched or compressed, while gravitational potential energy is related to an object’s height in a gravitational field.
What is the formula for elastic potential energy?
The formula for elastic potential energy is PE = 1/2 kx², where k is the spring constant and x is the extension or compression of the spring.
What is energy efficiency?
Energy efficiency is the ratio of useful energy output to the total energy input, often expressed as a percentage.
What is a renewable energy source?
A renewable energy source is an energy source that can be replenished naturally, such as solar, wind, or hydroelectric power.
What is non-renewable energy?
Non-renewable energy is energy from sources that cannot be replenished in a short time, such as fossil fuels.
What is the law of conservation of energy in relation to machines?
In machines, the law of conservation of energy states that the work output cannot exceed the work input.
What is the formula for power?
The formula for power is P = W/t, where P is power, W is work, and t is time.
What is the unit of power in the SI system?
The unit of power in the SI system is the watt (W).
True or False: Power is the rate at which work is done.
True: Power is the rate at which work is done or energy is transferred.
What is the relationship between energy and power?
Energy is the capacity to do work, while power is the rate at which work is done or energy is transferred.
What does the term ‘energy transfer’ refer to?
Energy transfer refers to the movement of energy from one location or form to another.
What is a system in physics?
A system in physics is a defined portion of the universe being studied, separated by boundaries.
What is the difference between closed and open systems?
A closed system does not exchange matter with its surroundings, while an open system can exchange both matter and energy.
What is heat energy?
Heat energy is the energy transferred between objects due to a temperature difference.
What is conduction?
Conduction is the transfer of heat energy through direct contact between materials.
What is convection?
Convection is the transfer of heat energy through the movement of fluids (liquids or gases).
What is radiation in terms of energy transfer?
Radiation is the transfer of energy through electromagnetic waves, such as light.
What is the formula for gravitational potential energy in relation to height?
The formula is PE = mgh, indicating that potential energy increases with height.
What is the relationship between mass and kinetic energy?
Kinetic energy is directly proportional to the mass of an object; increasing mass increases kinetic energy.
What is the significance of the spring constant (k) in elastic potential energy?
The spring constant (k) measures a spring’s stiffness; a higher k means the spring is stiffer.
What happens to energy when a ball is thrown into the air?
As the ball rises, kinetic energy is converted to gravitational potential energy; at the peak, kinetic energy is at its minimum.
What is the work-energy theorem?
The work-energy theorem states that the work done on an object equals the change in its kinetic energy.
Define ‘energy resource.’
An energy resource is a source of energy that can be utilized to produce work or power.
What is the role of energy in chemical reactions?
Energy is required to break bonds in reactants and is released when new bonds form in products.
What is a fossil fuel?
Fossil fuels are non-renewable energy sources formed from the remains of ancient organisms, such as coal, oil, and natural gas.
What is the concept of energy density?
Energy density is the amount of energy stored in a given system or region of space per unit volume or mass.
What is a calorie?
A calorie is a unit of energy defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius.
What is the difference between potential and kinetic energy?
Potential energy is stored energy based on position, while kinetic energy is energy of motion.
What is the formula for calculating gravitational potential energy at different heights?
PE = mgh can be used for different heights by substituting h with the new height.
What is the relationship between energy and temperature?
As temperature increases, the average kinetic energy of particles in a substance also increases.
What is the significance of energy transformations?
Energy transformations are crucial as they allow energy to be converted from one form to another to perform work.
What is the concept of a ‘heat engine’?
A heat engine is a device that converts thermal energy into mechanical work.
What is the efficiency of a heat engine?
The efficiency of a heat engine is the ratio of work output to heat input, expressed as a percentage.
What is an example of a non-renewable energy source?
An example of a non-renewable energy source is coal.
What is an example of a renewable energy source?
An example of a renewable energy source is solar energy.
What is the formula for calculating energy efficiency?
Energy efficiency = (useful energy output / total energy input) x 100%.
What is the role of energy in physical changes?
Energy is required to break intermolecular forces during physical changes, such as melting and boiling.
What is the principle of energy conservation in a pendulum?
In a pendulum, mechanical energy is conserved, transforming between kinetic and potential energy.
What happens to energy in a closed system?
In a closed system, energy can change forms but the total amount remains constant.
What is the impact of friction on energy?
Friction converts mechanical energy into thermal energy, reducing the efficiency of energy transfer.
What is an energy audit?
An energy audit is an assessment of energy use in a building, aimed at identifying opportunities for efficiency improvements.
What is the formula to calculate the energy of an object at rest?
An object at rest has no kinetic energy, so its energy is primarily potential energy if elevated.
What is the significance of heat capacity?
Heat capacity measures how much heat energy is required to change a substance’s temperature, influencing energy transfer.
What is the formula for potential energy in a spring?
The formula for potential energy in a spring is PE = 1/2 kx².
What is the significance of the Joule’s law?
Joule’s law states that the heat produced by an electric current is proportional to the resistance and the square of the current.
What is the difference between internal energy and thermal energy?
Internal energy is the total energy contained within a system, while thermal energy specifically refers to energy related to temperature.
What is a closed loop system in energy?
A closed loop system is one where energy is recycled back into the system without loss.
What role does energy play in biological systems?
In biological systems, energy is essential for growth, reproduction, and maintenance of cellular functions.
What is the relationship between energy and chemical bonds?
Energy is required to break chemical bonds and is released when new bonds are formed.
What is the significance of the first law of thermodynamics?
The first law of thermodynamics states that energy cannot be created or destroyed, only transformed.
What is the second law of thermodynamics?
The second law of thermodynamics states that energy transformations are not 100% efficient, and some energy is lost as heat.
