Jack tries to place magnets on the door of his refrigerator. he observes that the magnets don’t stick. he guesses that the door of the refrigerator is made of a nonmagnetic substance. what stage of scientific investigation does his guess represent?

ask questions

construct a hypothesis

explain the results

make observations

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

Examples of states of consciousness include a. daydreaming b. dreaming during sleep c. hypnosis d. all of the above

I) a gas contained within a piston-cylinder assembly undergoes two processes, a and b, between the same end states, 1 and 2, where p1 = 10 bar, v1 = 0.1 m3 , u1 = 400 kj and p2 = 1 bar, v2 = 1.0 m3 , u2 = 200 kj: ' process a: process from 1 to 2 during which the pressure-volume relation is pv = constant. ' process b: constant-volume process from state 1 to a pressure of 2 bar, followed by a linear pressure-volume process to state 2. kinetic and potential energy effects can be ignored. for each of the processes a and b, a) sketch the process on a p-v diagram. b) evaluate the work, in kj. c) evaluate the heat transfer, in kj.(ans : qb,12 = -65.0 kj)