Question

1. match the sentences with the terms.

thermal energy is transferred when particles of substances collide.
electromagnetic waves transfer thermal energy from one object to another.
this weakens the farther that objects are apart.
this increases the heavier an object is, and the rougher and larger the surface is between it and another object.
thermal energy is transferred by the movement of a heated gas or liquid.
choices
friction
conduction
radiation
convection
gravitational force

Explanation:

• Thermal energy is transferred when particles of substances collide: This is the definition of conduction. In conduction, heat is transferred through direct contact of particles.
• Electromagnetic waves transfer thermal energy from one object to another: This is radiation. Radiation does not require a medium and uses electromagnetic waves (like infrared) to transfer heat.
• This weakens the farther that objects are apart: Gravitational force. The gravitational force between two objects is inversely proportional to the square of the distance between them.
• This increases the heavier an object is, and the rougher and larger the surface is between it and another object: Friction. Friction force \(F_f=\mu N\), where \(N = mg\) (for a horizontal surface, \(N\) is the normal force and \(m\) is the mass of the object). Rougher surfaces have higher coefficient of friction \(\mu\).
• Thermal energy is transferred by the movement of a heated gas or liquid: Convection. Convection involves the movement of fluids (liquids or gases) due to density differences caused by heating.

Answer:

1. Thermal energy is transferred when particles of substances collide - conduction
2. Electromagnetic waves transfer thermal energy from one object to another - radiation
3. This weakens the farther that objects are apart - gravitational force
4. This increases the heavier an object is, and the rougher and larger the surface is between it and another object - friction
5. Thermal energy is transferred by the movement of a heated gas or liquid - convection