David was sitting in his hotel room reading a book, when he heard a knock at the door, and the sound of someone trying the door handle. He opened the door, where he saw a man whom he had never seen before. The man said, "I'm terribly sorry... I thought this was my room. Wrong floor, I guess. He then walked
off down the hall toward the elevator. David went back into his room, thought about what had just happened, and then phoned the front desk, suggesting they
call the police, since the man at the door had obviously been a thief.
Why was David so sure the man had been a thief?

layers of the earth affect the waves and these effects are seen on instruiments such as seimometers

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.