Answer:
Explanation:
As we know that the acceleration due to gravity decreases with height.
At certain height it will get to the half of its value on the surface of the earth.
As we know that the weight on the surface of the earth is given as:
where:
m = mass of the object
g = acceleration due to gravity of the substance
Since mass of the substance is constant so the variation is weight is possible only due to change in the acceleration due to gravity.
<u>We know that the variation of the acceleration due gravity with height is given as:</u>
where:
value to acceleration due to gravity at height h
g = acceleration due to gravity at the earth's surface
h = height of the object
R = radius of the earth = 
according to question the weight becomes half, so,:
is the height a rocket has to go above Earth's surface before its weight is half of what it is on Earth.
During a total lunar eclipse, Earth completely blocks direct sunlight from reaching the Moon. The only light reflected from the lunar surface has been refracted by Earth's atmosphere. ... Due to this reddish color, a totally eclipsed Moon is sometimes called a blood moon.
Answer:
Under assumption that all food energy that needs the horse is transformed into work, then the horse needs approximately 3 megajoules of food energy to work for 1 hour.
Explanation:
Since horse is working steadily, the power experimented by the horse (
), measured in watts, is at constant rate. Then, the work needed by the horse (
), measured in joules, is equal to that power multiplied by time (
), measured in seconds. That is:
(1)
If we know that 
and 
, then the work needed for the horse is:
Under assumption that all food energy that needs the horse is transformed into work, then the horse needs approximately 3 megajoules of food energy to work for 1 hour.
Answer:
v = wavelength * frequency
frequency = 5200 m/s / .2 m = 26000 / sec
20,000 / sec is optimistic for the upper frequency of human hearing
So 26,000 is above the hearing range for human ears
