A person holds a 4.0 kg block at position A, 30 cm above ground, in contact with an uncompressed vertical spring with a spring constant of 500 N/m. the person gently lowers the block from rest at position A to rest at position B. which of the following describes the change in the energy of the block-spring-Earth system as a result of the block being lowered?
(a) The energy decreases by approx. 1.5 J
(b) The energy decreases by approx. 2.5 J
(c) The energy increases by approx. 4.0 J
(d) The energy of the system does not change.

Aresearcher plans to conduct a test of hypotheses at the 1% significance level. she designs her study to have a power of 0.90 at a particular alternative value of the parameter of interest. the probability that the researcher will commit a type ii error for the particular alternative value of the parameter at which she computed the power is: a. 0.90. b. 0.01. c. 0.10. d. equal to 1

The key to stability is feedback between the reservoir and the fluxes into and/or out of the reservoir. assume that the rate of outflow from a reservoir depends on the size of the reservoir according to the following relationship: outflow rate= k x (size of reservoir), where k is a constant. a reservoir of water has a volume of 5000 liters, and the rate of outflow at steady state is 25 liters per minute. what is k? (give both the numerical value and its units.) what is the residence time? what is the relationship between k and the residence time?

If a substance is in the gas phase, which of qualities of the gas will stay constant? a: volume b: mass c: shape d: position of particles