Avisitor to a lighthouse wishes to determine the height of the tower. she ties a spool of thread to a small rock to make a simple pendulum, which she hangs down the center of a spiral staircase of the tower. the period of oscillation is 10.1 s. the acceleration of gravity is 9.8 m/s 2 . what is the height of the tower?

To solve this problem we must rely on the equations of the simple harmonic movement that define the period as a function of length and gravity as

Where

l = Length

g = Gravity

Re-arrange to find L,

Our values are given as

Replacing,

Therefore the height would be 25.348m

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.