Astronauts land on another planet and measure the density of the atmosphere on the planet surface. They measure the mass of a 500 cm3 conical flask plus stopper as 457.23 g. after removing the air, the mass is 456.43 g (1 m3 = 1000 litres). What is the best estimate of the density of the air? A) 0.0000016 kg/m3
B) 0.0016 kg/m3
C) 0.16 kg/m3
D) 1.6 Kg/m3

dopamine..

"it was found that some people who were taking the drug l-dopa to raise their levels of dopamine were developing schizophrenic-like symptoms supporting research a strength of the dopamine hypothesis is that there are many studies which have shown support for the neurochemical explanation."

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.