Explain Energy Transfer Through Interactions - Physics

Identify the energy transfer mechanism when a hot mug warms a colder hand touching it.

Heating transfers energy from mug to hand. Temperature difference drives thermal energy flow.
What is the energy conservation statement for a closed system with no external work or heating?

Total energy stays constant; energy only changes form within the system. Energy cannot be created or destroyed in isolated systems.
Identify the energy transfer mechanism when friction slows a sliding book on a table.

Work done by friction transfers energy to thermal energy. Friction does negative work, converting kinetic to thermal energy.
What is the definition of power as a rate of energy transfer?

Energy transferred per unit time. Measures how quickly energy is transferred or transformed.
Identify the energy transformation when an object falls freely (ignore air resistance).

Gravitational potential energy transfers to kinetic energy. Height decreases while speed increases, conserving total energy.
What is the definition of kinetic energy for a moving object?

Energy of motion. Depends on mass and speed of the object.
Which sign of work occurs when the force component is opposite the displacement?

Negative work, $W<0$ . Force opposes motion, removing energy from system.
Identify the sign of work when the force is opposite the displacement direction.

Negative work. Force opposes motion, removing energy from the system.
State the formula for work done by a constant force parallel to motion.

$W=Fd$ . Force and displacement must be parallel.
Identify the energy transfer mechanism when sunlight warms a black surface.

Radiation. Electromagnetic waves carry energy without a medium.
What is the definition of elastic potential energy stored in a spring?

Energy stored due to elastic deformation. Springs store energy when compressed or stretched.
State the formula for elastic potential energy in a spring with constant $k$ and extension $x$ .

$E_e=\frac{1}{2}kx^2$ . Energy stored is proportional to displacement squared.
What is the conservation of energy statement for an isolated system?

Total energy of the system remains constant. Energy cannot be created or destroyed in isolated systems.
What is the definition of a system in energy analysis?

The object or group of objects chosen for study. Defines the boundary for energy accounting.
State the general formula for work done by a constant force at angle $\theta$ to displacement.

$W=Fd\cos\theta$ . Accounts for force component along displacement.
What is the definition of thermal energy transfer by radiation?

Energy transfer by electromagnetic waves. No medium needed; travels at speed of light.
What is the definition of elastic potential energy stored in a stretched or compressed spring?

Energy stored due to elastic deformation. Springs store energy when compressed or stretched.
Identify the energy transfer mechanism when a person pushes a box across the floor.

Work. Applied force causes displacement, transferring energy.
State the formula for average power in terms of work and time.

$P=\frac{W}{t}$ . Average power equals work divided by time interval.
What does the work-energy theorem state for net work and kinetic energy change?

$W_\text{net} = \Delta K$ . Net work equals change in kinetic energy.
What is the definition of heating (thermal transfer) as an energy transfer mechanism?

Energy transfer due to a temperature difference. Heat flows from hot to cold spontaneously.
What is the definition of gravitational potential energy near Earth's surface?

Energy due to height in a gravitational field. Objects gain energy when lifted against gravity.
What is the definition of thermal energy transfer by convection?

Energy transfer by bulk motion of a fluid. Moving fluids carry thermal energy with them.
What is the definition of energy transfer in a physical interaction?

Energy moving from one system to another due to forces or heating. Forces do work or temperature differences cause heating.
State the formula for kinetic energy.

$K = \frac{1}{2}mv^2$ . Half mass times velocity squared gives kinetic energy.
State the formula for kinetic energy of a mass $m$ moving at speed $v$ .

$E_k=\frac{1}{2}mv^2$ . Kinetic energy is proportional to mass and speed squared.
State the formula for gravitational potential energy change near Earth.

$\Delta E_g=mg\Delta h$ . Change in height determines potential energy change.
What is the definition of gravitational potential energy near Earth for height $h$ ?

Energy stored due to position in a gravitational field. Higher position stores more gravitational energy.
State the formula for work done by a constant force at angle $\theta$ to displacement.

$W = Fd\cos\theta$ . Accounts for angle between force and displacement vectors.
What is the definition of the surroundings in energy analysis?

Everything outside the chosen system that can interact with it. Includes all matter and fields not in the system.
What is the definition of power in terms of energy transfer rate?

Rate of energy transfer per time. Measured in watts (W) or joules per second.
State the formula for elastic potential energy in a Hooke's law spring.

$U_s = \frac{1}{2}kx^2$ . Half spring constant times displacement squared.
What is the definition of thermal energy transfer by conduction?

Energy transfer through direct contact within a material. Heat flows through materials via molecular collisions.
What is the definition of work as an energy transfer mechanism?

Energy transfer by a force acting through a displacement. Force must move object to transfer energy.

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