Question

Which statement best describes energy in an open system?

All energy and matter are contained within the system.

Energy and matter flow into and out of the system.

Matter flows into and out of the system; energy does not.

There is no energy in an open system; there is matter.

Answer 1

The second. The first applies only to the entire universe, the third is logically impossible, since energy is a property of matter and ipso facto a flow of matter is a flow of energy, and the fourth is poorly defined -- it's unclear what "energy" means in this context -- but for the same reason probably equally illogical.

Answer 2

When a sound source is moving toward the observer, the observer will hear a

higher pitch due to the change to a lower frequency.

higher pitch due to the change to a higher frequency.

lower pitch due to the change to a higher frequency.

lower pitch due to the change to a lower frequency.