Answer:
Hipparchus was an ancient Greek who classified stars based on the brightness in 129 B.C. He grouped the brightest stars and ranked them 1 (first magnitude) and dimmest stars as 6 (sixth magnitude). Thus, the smaller numbers indicated brighter stars. Now, the scale extends in negative axis as well. More the negative number, brighter is the star. For example, Sun has magnitude -26.74.
This the apparent magnitude which means the classification is based on the brightness of the star as it appears from the Earth.
Answer:
• riding on a Ferris wheel whose entrance and exit are the same
• walking around the block, starting from and ending at the same house
• running exactly one lap around a racetrack
Explanation:
Displacement simply means the.change in position of an object. In a situation whereby the initial and final position are thesame, the displacement will be zero.
The statements that describe a situation with a displacement of zero include:
• riding on a Ferris wheel whose entrance and exit are the same
• walking around the block, starting from and ending at the same house
• running exactly one lap around a racetrack
Answer:
Explanation:
The calcite Crystal can be identified by carrying out an acid test on it. This is done by bringing it in contact with a weak acid which cause crack in it structure. Hence a little of carbondioxide gas is released.
Since diamond is the hardest object,it can be identified on a Mohs scale. Likewise it can be tested by bringing it in contact with a newspaper, if the letters on the paper are not seen, that shows it is a pure diamond.
Window glass is identified by the code on it.
While Quartz Crystal is identified by scratch test. When it is used to scratch all other softer stones and metal, it leaves mark on them.
The work done to accelerate the acrobat is given by
where F is the force applied and d the distance of application of the force.
If the barrel is 3.05 m long, then d=3.05 m. Therefore we can find the force:
Answer:
The moon revolves around Earth because Earth is larger than the moon, so it is heavier, and has a greater gravitational pull. The plane of the moon's orbit is very close to the plane of Earth's orbit around the Sun. This is why planets revolve around the Sun, because it is larger, so therefore it has a greater gravitational pull.
