To model the velocity distribution in the curved inlet section of a wind tunnel, the radius of curvature of the streamlines is expressed as R=LR0/2n. As a first approximation assume the air speed along each streamline is V=20 m/s. Evaluate the pressure change from n=0 to the tunnel wall at n=L/2, if L=150 mm and R0=0.6 m.

Imagine you had to physically add electrons, one at a time, to a previously neutral conductor. you add one electron very easily, but the second electron requires more work. in your initial post to the discussion, explain why this is. also, what happens to the work needed to add the third, fourth, fifth, and subsequent electrons

Aspring has a natural length of 8 m. if a 12-n force is required to keep it stretched to a length of 10 m, how much work w is required to stretch it from 8 m to 16 m? (round your answer to two decimal places.)

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.