A given container of 5.0 kg of water maintains a constant temperature over 24 hours. If its mass doesn't change, what statements would support identifying it as a closed system. I. Only energy was exchanged with its surroundings.
II. Its mass was constant because the water lost to evaporation was replaced with an equal volume of water.
III. It didn't exchange matter or energy with its environment.
IV. External work was used to maintain its internal energy.

A) III
B) l and III
C) II and IV
D) I and IV​

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)

The chart shows daniela’s run through her race. what is her velocity? 1.5 m/s 2 m/s 2.5 m/s 5 m/s