If the mass of a portion is 1.67 x 10-27kg and the mass of an electron is 9.11 x 10-31kg, calculate the force of gravitation between: i. a proton and an electronii. two electronsiii. two protons. Take G= 6.67 x 10-11 Nm2kg-2, distance between the protons = 4.0m., distance between the electrons = 2 x 10-2m, distance between the proton and the electron = 5.4 x 10-11m ​

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?

Currents in dc transmission lines can be 100 a or higher. some people are concerned that the electromagnetic fields from such lines near their homes could pose health dangers. for a line that has current 150 a and a height of 8.0 m above the ground, what magnetic field does the line produce at ground level? express your answer in teslas and as a percentage of the earth’s magnetic field, which is 0.50 g. is this value cause for worry?