Question

7 a force that opposes motion between two surfaces in contact is called
a) gravity
b) friction
c) pressure
d) tension
8 the sum of potential and kinetic energy of an object is called:
a) total energy
b) mechanical energy
c) thermal energy
d) radiant energy
9 a system that exchanges both matter and energy with its surroundings is called a(n):
a) closed system
b) isolated system
c) open system
d) equilibrium system
10 the movement of thermal energy from one object or place to another is called:
a) temperature
b) heat transfer
c) conduction only
d) thermal equilibrium
11 the process of maintaining a constant internal environment in the body is called:
a) temperature regulation
b) heat transfer
c) homeostasis
d) thermal energy
12 the internal energy of a substance due to the motion of its atoms and molecules is called:
a) heat
b) temperature
c) thermal energy
d) kinetic energy
13 a measure of the average kinetic energy of molecules in a substance is:
a) heat
b) temperature
c) thermal energy
d) energy transformation

Explanation:

1. Friction is the force that opposes motion between two surfaces in contact. Gravity is the force of attraction between objects, pressure is force per unit area, and tension is a pulling force.
2. Mechanical energy is the sum of potential and kinetic energy. Total energy can include other forms like thermal, etc. Thermal energy is related to heat, and radiant energy is from electromagnetic waves.
3. An open system exchanges both matter and energy. A closed system exchanges only energy, an isolated system exchanges neither, and an equilibrium system is in a stable state.
4. Heat transfer is the movement of thermal energy. Temperature is a measure of hotness/coldness, conduction is a mode of heat transfer (but not the overall movement), and thermal equilibrium is when there's no net heat transfer.
5. Homeostasis is maintaining a constant internal environment. Temperature regulation is part of it, heat transfer is energy movement, and thermal energy is a form of energy.
6. Thermal energy is the internal energy due to atomic/molecular motion. Heat is energy transfer, temperature is a measure, and kinetic energy is of motion (but thermal energy is specific to internal atomic/molecular).
7. Temperature is a measure of the average kinetic energy of molecules. Heat is energy transfer, thermal energy is the total internal, and energy transformation is changing energy forms.

Answer:

1. B. Friction
2. B. Mechanical energy
3. C. Open system
4. B. Heat transfer
5. C. Homeostasis
6. C. Thermal energy
7. B. Temperature