The work done is the product between the intensity of the force applied F, the amount of the displacement d of the book and the cosine of the angle

between the direction of the force and the direction of the displacement:

In our problem, the student is lifting the book, so he is applying a force directed upward, and the book is moving upward, so F and d are parallel and therefore the angle is zero, so

Therefore, the work done is
The angle of the Sun above the horizon, which is the solar altitude, influences the intensity ofsolar radiation received at Earth’s surface. At the place on Earth where the Sun is directlyoverhead, the local solar altitude has its maximum value of 90 degrees and solar rays are mostconcentrated. Whenever the Sun is positioned lower in the sky, solar radiation spreads over alarger area of Earth’s horizontal surface and thus is less intense. Solar radiation reaches theplanet essentially as parallel beams of uniform intensity. The nearly spherical Earth presents acurved surface to incoming solar radiation so that the noon solar altitude always varies withlatitude. The intensity of solar radiation actually striking Earth’s atmosphere is greatest at thelatitude where the noon Sun is in the zenith and decreases with distance north and south of thatlatitude. Decreasing solar altitude lengthens the path of the Sun’s rays through the atmosphere.As the path lengthens, the greater interaction of solar radiation with clouds, gases and aerosols<span>reduces its intensity</span>
A default route is an exceptional kind
of static route because the subnet and network you are identifying
as the target for the traffic that it would equal to all zeros. The characteristic
of a default static route would be it classifies the gateway IP address to
which the router directs all IP packets for which it does not have a knowledge
or static route.