Acylindrical bar of metal having a diameter of 18.7 mm and a length of 200 mm is deformed elastically in tension with a force of 53200 n. given that the elastic modulus and poisson's ratio of the metal are 66.3 gpa and 0.32, respectively, determine the following: (a) the amount by which this specimen will elongate in the direction of the applied stress.
(b) the change in diameter of the specimen. indicate an increase in diameter with a positive number and a decrease with a negative number.

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.