ANSWER
EXPLANATION
First, let us make a sketch of the question:
From the diagram:
=> black line represents North
=> green line represents East
=> blue line represents West
=> red line represents South
From the diagram, we see that at the end of his journey, he returns to his start point.
Since displacement is the measure of the change in the position of an object and the boy's position did not change after the journey, his displacement is:
From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is
Here,
f = Focal Length
R = Radius
Rearranging to find the radius we have,
Replacing with our values,
R = 2(13.8cm)
R = 27.6cm
Therefore the radius of the spherical surface from which the mirror was made is 27.6cm
Kinetic energy =(1/2) (mass) (speed²)
First object: KE = (1/2) (2 kg) (2m/s)² = 4 joules during the lift.
Second object: KE = (1/2) (4kg) (3 m/s)² = 18 joules during the lift.
The second object has more kinetic energy while it's being lifted
than the first object has while it's being lifted. Once they reach their
final heights and stop, neither object has any kinetic energy.
The existence of photosynthetic organisms, particularly the blue-green algae, are the organisms responsible for changing the early atmosphere of the Earth. These organisms came from rock formations found throughout Earth and are responsible for feeding off on the carbon dioxide that was abundant in its atmosphere. As they have learned to feed-off carbon dioxide, they in turn have transformed this compound and produced oxygen.
Scientists have also proven that rocks and other sediments contained abundant amounts of trapped oxygen. Through time when the rocks have withered and formed into sediments these oxygen gases are released into the air and got trapped within the atmosphere overpowering the levels of carbon dioxide.
This phenomenon is very important throughout the history of Earth because the Earth became a habitable planet where several species can thrive. This phenomenon has also led to the several geographical changes that the Earth has undergone to because it cooled-down its overall temperature.
