What is a closed system?

A. A system in which no work is done

B. A system that can exchange matter with its surroundings

C. A system that cannot exchange matter with its surroundings

D. A system in which no heat flows

What is the surface temperature of a distant star having a peak wavelength of 475 nm?

The accepted value for the density of iron is 7.87 g/cm3. a student records the mass of a 20.00 cm3 block of iron as 153.8 grams. what is the percent error for the density measurement? a. 2.29% b. 2.34% c. 19.4% d. 7.69%

An electron (m=9.11x10^-31 kg) moves in a circle whose radius is 2.00x10^-2 m. If the force acting on the electron is 4.60x10^-14 N, what is it's speed?

Which universal force acts on protons and neutrons in an atom's nucleus? strong nuclear force magnetic force gravitational force electrie force

An ideal refrigerator extracts 500 joules of heat from a reservoir at 295 K and rejects heat to a reservoir at 493 K. What is the ideal coefficient of performance and how much work is done in each cycle?

An ice cube is dropped into a glass of water. Describe the motion of the ice cube and explain why it moves this way

How does the overtone number relate to the standing wave pattern number

Which of the following statements about Em waves is true? A. Em waves all have the same speed B. Em waves all have the same wavelength C. Em waves only travel through water D. Em waves all have the same amount of energy

A teacher has asked four students to state a scientific theory. Which student is correct?

What are the two main currents that affect the US on the east and west coast?