Heat is added to a substance, but its temperature does not rise. Which one of the following statements provides the best explanation for this observation?

Heat is added to a substance, but its temperature does not rise. Which one of the following statements provides the best explanation for this observation? the substance must be a gas. the substance must be a non-perfect solid. the substance undergoes a change of phase. the substance has unusual thermal properties. the substance must be cooler than its environment.

(A) The substance must be a gas.

B) The substance must be a non-perfect solid.

C) The substance undergoes a change of phase.

D) The substance has unusual thermal properties.

E) The substance must be cooler than its environment.

Answer is c was correct answer

truck y has a greater velocity than truck x.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me