Forced air at t 25 c and v 10 m/s is used to cool electronic elements on a circuit board. one such element is a chip, 4 mm 4 mm, located 120 mm from the leading edge of the board. experiments have revealed that flow over the board is disturbed by the elements and that convection heat transfer is correlated by an expression of the form estimate the surface temperature of the chip if it is dissipating 30 mw.

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?

Newtons view of arrangement of the universe. don't copy from anywhere.

Ahair dryer is basically a duct in which a few layers of electric resistors are placed. a small fan pulls the air in and forces it through the resistors where it is heated. air enters a 1200 w hair dryer at 100 kpa and 22°c and leaves at 47°c. the cross-sectional area of the hair dryer at the exit is 60 cm2. neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine (a) the volume flow rate of air at the inlet and (b) the velocity of the air at the exit.