Why would U-238 or Pb-206 be more useful than C-14 when dating rocks?

The energy equivalent of the rest mass of an electron is

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.

Aboat travels at 15 m/s in a direction 45° east of north. the boat then turns and travels at 18 m/s in a direction 5° north of east. what is the magnitude of the boat's resultant velocity? round your answer to the nearest whole number. /s what is the direction of the boat's resultant velocity? round your answer to the nearest whole degree. ° north of east