Energy Types and Transformations

These flashcards cover key vocabulary related to energy types, transformations, and principles in physics.

Kinetic Energy (KE)

The energy of motion, calculated as KE = 0.5 * m * v², where m is mass and v is speed.

Potential Energy (PE)

Stored energy, mainly gravitational potential energy, calculated as PE = m * g * h, where g is the acceleration due to gravity and h is height.

Energy Transformation

The process of changing energy from one form to another, such as transforming chemical energy into mechanical energy.

Energy Transfer

The movement of energy from one object or location to another without changing its form.

Mechanical Energy

The sum of kinetic and potential energy in an object that is being used to do work.

Conservation of Energy

A principle stating that energy cannot be created or destroyed, only transformed from one form to another.

Gravitational Potential Energy

Potential energy related to the height of an object in a gravitational field, calculated as PE = m * g * h.

Chemical Potential Energy

Energy stored in the bonds of chemical compounds, which can be released during a chemical reaction.

Radiant Energy

Energy carried by light, which can be transformed into other types of energy, such as thermal energy.

Thermal Energy

The total energy of all the particles in an object, often associated with temperature and heat transfer.

Elastic Potential Energy

Energy stored in elastic materials as the result of their stretching or compressing.

Electric Potential Energy

Energy a charged object possesses due to its position in an electric field.

Sound Energy

Energy produced by vibrating sound waves.

Mechanical Energy Transformation

The process where mechanical energy is converted from one form to another, such as from kinetic to potential energy.

Friction

A force that opposes motion between two surfaces, often resulting in the conversion of kinetic energy into thermal energy.

Work

A measure of energy transfer that occurs when an object is moved over a distance by an external force.

How do you calculate gravitational potential energy (PE)?

Gravitational potential energy can be calculated using the formula: PE = m \times g \times h, where $m$ is mass in kilograms, $g$ is the acceleration due to gravity (approximately 9.81 \, m/s^2), and $h$ is height in meters.

What is the formula for kinetic energy (KE)?

The formula for kinetic energy is KE = \frac{1}{2} mv^2, where $m$ is mass in kilograms and $v$ is velocity in meters per second.

How does mass affect kinetic energy?

Kinetic energy is directly proportional to the mass of the object; as mass increases, kinetic energy increases.

How does velocity affect kinetic energy?

Kinetic energy is proportional to the square of velocity; if velocity doubles, kinetic energy increases by a factor of four.

What units are used for kinetic energy?

Kinetic energy is measured in joules (J), which is the standard unit of energy in the International System of Units (SI).

What is potential energy?

Potential energy is the energy stored in an object due to its position or state; it has the potential to do work.

What is the formula for gravitational potential energy?

The formula for gravitational potential energy is PE = m \times g \times h, where $m$ is mass, $g$ is acceleration due to gravity, and $h$ is height.

What factors affect gravitational potential energy?

Gravitational potential energy depends on the object's mass, the height above a reference point, and the acceleration due to gravity.

What is elastic potential energy?

Elastic potential energy is the energy stored in elastic materials as the result of their stretching or compressing.

Can potential energy be converted to kinetic energy?

Yes, potential energy can be converted to kinetic energy, such as when an object falls, transforming its stored energy into motion.

How do you calculate velocity from kinetic energy?

To find velocity from kinetic energy, use the formula: v = \sqrt{\frac{2KE}{m}}, where $KE$ is kinetic energy and $m$ is mass.

What is the relationship between kinetic energy and velocity?

Kinetic energy increases with the square of velocity; doubling the velocity quadruples the kinetic energy.

What units are used for measuring velocity?

Velocity is measured in meters per second (m/s) in the International System of Units (SI).

If an object has a mass of 2 kg and kinetic energy of 16 J, what is its velocity?

Using the formula v = \sqrt{\frac{2KE}{m}}, the velocity would be v = \sqrt{\frac{2 \times 16}{2}} = \sqrt{16} = 4 \, m/s.

How do you calculate mass from kinetic energy?

To find mass from kinetic energy, use the formula: m = \frac{2KE}{v^2}, where $KE$ is kinetic energy and $v$ is velocity.

What happens to mass if kinetic energy is doubled while velocity remains constant?

If kinetic energy is doubled while velocity is constant, the mass would also double, as they are directly related via the kinetic energy formula.

What is the relationship between kinetic energy, mass, and velocity?

Kinetic energy is directly proportional to both mass and the square of velocity; increasing either will increase kinetic energy.

If an object has a kinetic energy of 20 J and a velocity of 5 m/s, what is its mass?

Using the formula m = \frac{2KE}{v^2}, the mass would be m = \frac{2 \times 20}{5^2} = \frac{40}{25} = 1.6 \, kg

How do you calculate mass from gravitational potential energy?

To find mass from gravitational potential energy, use the formula: m = \frac{PE}{g \times h}, where $PE$ is gravitational potential energy, $g$ is the acceleration due to gravity, and $h$ is height.

What is the relationship between potential energy, mass, and height?

Gravitational potential energy increases with both mass and height; if either increases, the potential energy increases.

If an object has a gravitational potential energy of 50 J, a height of 10 m, what is its mass?

Using the formula m = \frac{PE}{g \times h} (assuming g \, \approx \, 9.81 \, m/s^2), the mass would be m = \frac{50}{9.81 \times 10} \approx 0.51 \, kg.

What constants are commonly used for gravitational acceleration?

The standard value for gravitational acceleration ($g$) on Earth is approximately 9.81 \, m/s^2.

What influences gravitational potential energy besides mass?

Gravitational potential energy is influenced by height above a reference point; higher positions correspond to greater potential energy.

How do you calculate height from gravitational potential energy?

To find height from gravitational potential energy, use the formula: h = \frac{PE}{m \times g}, where $PE$ is gravitational potential energy, $m$ is mass, and $g$ is the acceleration due to gravity.

What happens to height if potential energy increases while mass remains constant?

If potential energy increases while mass remains constant, height must also increase, as they are directly related through the potential energy formula.

If a mass of 2 kg has a gravitational potential energy of 40 J, what is its height?

Using the formula h = \frac{PE}{m \times g} (assuming g \approx 9.81 \, m/s^2), the height would be h = \frac{40}{2 \times 9.81} \approx 2.03 \, m.

What is the effect of increasing mass on gravitational potential energy at a constant height?

Increasing mass while keeping height constant will increase gravitational potential energy, since potential energy is directly proportional to mass.

What is a common application of calculating height using potential energy?

Calculating height is often used in physics problems related to the energy conservation of objects in free fall or object placement at different heights.

What is the conservation of energy principle in physics?

The conservation of energy principle states that energy cannot be created or destroyed, only transformed from one form to another.

How do you calculate the speed of an object at its lowest point using conservation of energy?

Use the formula: mgh = \frac{1}{2}mv^2 where (m) is mass, (g) is the acceleration due to gravity, (h) is the initial height, and (v) is the speed at the lowest point.

What variables are needed to calculate the speed of an object at its lowest point according to conservation of energy?

The mass of the object (m), the height from which it falls (h), and the acceleration due to gravity (g).

What is the formula to derive the speed of an object at its lowest point from the conservation of energy equation?

Rearranging the conservation of energy equation: v = \sqrt{2gh} to find the speed (v) at the lowest point.

What is nuclear fusion in the context of the Sun and stars?

Nuclear fusion is the process where two light atomic nuclei combine to form a heavier nucleus, releasing a significant amount of energy.

What elements primarily undergo fusion in the Sun?

In the Sun, hydrogen nuclei primarily undergo fusion to form helium nuclei.

What is the main process of fusion that occurs in the Sun?

The main process is the proton-proton chain reaction, where hydrogen nuclei fuse to create helium, releasing energy.

How does fusion in the Sun generate energy?

Fusion releases energy in the form of light and heat, sustaining the Sun's temperature and energy output.

What are the conditions required for fusion to occur in stars?

High temperature (millions of degrees) and high pressure, which are met in the core of stars.

What is an alpha decay reaction?

Alpha decay is a nuclear reaction in which an atomic nucleus emits an alpha particle (two protons and two neutrons), resulting in a decrease in the atomic number by two and the mass number by four.

What happens during a beta decay reaction?

In beta decay, a neutron in an atomic nucleus transforms into a proton and emits a beta particle (an electron or positron), increasing the atomic number by one and leaving the mass number unchanged.

What is gamma decay?

Gamma decay involves the emission of gamma radiation (high-energy photons) from an excited atomic nucleus as it transitions to a lower energy state, with no change in atomic number or mass.

What are the characteristics of alpha particles?

Alpha particles are positively charged, relatively heavy, and have low penetration power; they can be stopped by a sheet of paper.

How do beta particles compare to alpha particles?

Beta particles are lighter, negatively charged (electrons) or positively charged (positrons), and have greater penetration power than alpha particles, but can be stopped by a layer of plastic or glass.

What protective measures are needed against gamma radiation?

Gamma radiation requires dense materials for shielding, such as lead or thick concrete, due to its high penetration power.

What is a nuclear reactor?

A nuclear reactor is a device used to initiate and control a sustained nuclear chain reaction.

How does nuclear fission occur in a reactor?

Nuclear fission occurs when the nucleus of a heavy atom, such as uranium-235 or plutonium-239, splits into two smaller nuclei along with a few neutrons and a large amount of energy.

What role do control rods play in a nuclear reactor?

Control rods are used to control the rate of the nuclear reaction by absorbing excess neutrons, thus preventing the reaction from becoming too rapid.

What is the purpose of coolant in a nuclear reactor?

Coolant, often water or liquid metal, is used to transfer heat away from the reactor core to produce steam, which drives turbines to generate electricity.

What are the main safety measures in a nuclear reactor?

Safety measures include containment structures, redundant cooling systems, and emergency shutdown systems to prevent accidents or the release of radioactive materials.

What is the process of steam generation in a nuclear reactor?

The heat generated from fission is used to heat water, turning it into steam, which then drives a turbine connected to a generator.

What is the significance of the reactor core?

The reactor core contains the nuclear fuel and is where the fission reactions take place, producing heat.

What are the potential risks of nuclear reactors?

Potential risks include radiation exposure, nuclear accidents, and the challenge of managing nuclear waste.

System

A group of objects or components that are being studied in terms of energy and its transformations.

Open System

A system where both energy and matter can enter or leave.

Closed System

A system where matter cannot enter or leave, but energy can be exchanged.

Isolated System

A system where neither matter nor energy can enter or leave.