If an airplane flies at 450 m/s around the planet, and the earth's circumference is about 4.01 x 107 m, calculate the time dilation for an around-the-world trip. ignore the earth's rotation and gravity 4.) in the rest frame of the sample, the number of muons at time t is given by n(t) = noe t/7, where no is the number at 0, and t is the mean lifetime (or "half life") of 2.2 us. a) assume the muons are produced at a height of 6.0 km, and head toward the ground as a speed of 0.91c. what fraction will reach the ground? b) what fraction would reach the ground if classical mechanics were correct?

most of them using statistics and defining how things are being measured

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.