Consider a cylinder of 20 mm in diameter (d) and 100 mm in length (l) that is installed in a duct. air moves in cross flow over the side surface of the cylinder at a temperature (t∞) and velocity (v) of 33.7 °c and 30 m/s, respectively. if the average cylinder surface temperature (ts) is maintained at 120 °c, what is the required power generation of the cylinder? note: (1) air properties can be found from table a.4 in the textbook. (2) the heat loss from the top and bottom surface of the cylinder is negligible. (3) use churchill and bernstein method to solve it.

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.