The period T of a pendulum is given by:

where L is the length of the pendulum while

is the gravitational acceleration.
In the pendulum of the problem, one complete vibration takes exactly 0.200 s, this means its period is

. Using this data, we can solve the previous formula to find L:
Answer:
C. Overcome Friction
Explanation:
When using any machine usually those with moving parts, you may notice heat forming near the areas where most movement occurs. As friction continues, more energy is used up and released as heat. For that reason, the efficiency of a machine will forever be less than 100%
Answer:0.0704 kg
Explanation:
Given
initial Absolute pressure
=210+101.325=311.325



as the volume remains constant therefore



therefore Gauge pressure is 337.44-101.325=236.117 KPa
Initial mass 

Final mass 

Therefore
=0.91-0.839=0.0704 kg of air needs to be removed to get initial pressure back
13.6) When any boat displaces a weight of water equal to its own weight, it floats.
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. ... Refraction not only affects visible light rays, but all electromagnetic radiation, although in varying degrees.
So in short, the answer is D.
(My answer got deleted because it didnt explain which is dumb)