Answer: The rising and setting of the Sun.
The appearance and disappearance of the Moon.
Changes in season.
Appearance and disappearance of the Stars.
Explanation: The rising and setting of the Sun helps can be used as a standard to determine time since the rissing and setting of the Sun occurs at similar time and interval in a given geographical ocation.
The appearance and disappearance of the Moon which occurs during the night and early hours of the morning is similar in a given geographical locationation so it can be used as a standard for Time.
Change in season is another natural phenomenon which occurs at similar times in a given geographical location like Winter/summer, rainy/dry etc can be used as standards for time.
The appearance and disappearance of the Stars can also b used as standards for time in a given geographical location.
A rock formed from the crystallization of magma is called an igneous rock. We know this rock forms from the cooling and / or solidification of lava or magma - usually from volcanoes, most of the time.
Answer:
Because the light reflects multiple times until it gets to the Cassegrain focus.
Explanation:
The Cassegrain design can be seen in a reflecting telescope. In this type of design the light is collected by a concave mirror, and then intercepted by a secondary convex mirror, and sends it down to a central opening in the primary mirror (concave mirror), in which a detector is placed (Cassegrain focus)
Since, the light is reflected many times due to Cassegrain design, that leads to shorter telescopes.
Answer:
Explanation:
Equation of the rocket is,
Here, v' is the relative velocity of rocket.
In space F is zero.
So,
Now the momentum can be obtained by multiply by m on both sides.
Now for maxima, 
Now,
Therefore, the mass of the rocket while having maximum momentum is 
A body that is falling is an example of gravity at work.
