Atmospheric air is in parallel flow (u[infinity] = 10 m/s, T[infinity] = 15°C) over a flat heater surface that is to be maintained at a temperature of 90°C. The heater surface area is 0.25 m2, and the airflow is known to induce a drag force of 0.15 N on the heater. What is the electrical power needed to maintain the prescribed surface temperature?

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)

Sort the images based on whether there's a force of attraction or repulsion between the magnets shown. attraction repulsion

Aplayer uses a hockey stick to push a puck at a constant velocity across the ice. the weight of the puck is 170 n. the coefficient of friction is 0.0600. with what force must the player push the puck so that his force just equals the frictional force? 28.3 n 0.999 n 0.102 n 0.0104 n