Air enters the duct of an air-conditioning system at 42∘C and 66 kPa at a velocity of 2 m/s. Mass flow rate is 2 kg/s. Heat is transferred to the air in the duct from the surroundings. There is also an electric power input of 25 kW. The air exits the duct at 57 ∘C. Determine (a) the heat transfer rate to the duct, (b) density of the air entering the duct, (c) the volume flow rate at the inlet, and (d) diameter of the duct.[ R=0.287kPa *m^3/kg* K, :Cp=1.005 kJ/kg* C

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

Avoltaic cell converts chemical energy to

What are the starting materials for nuclear fission? two small nuclei two large nuclei a neutron and a large nucleus a neutron and a small nucleus