Answer:
As the planets are very small and dark in comparison with stars, it makes them very hard to be found from earth.
Explanation:
Astronomy, of course, has a solution for this. As astronomers can't observe planets directly, they decided to observe the stars and search for the effects that planets have on them.
There are many ways of observing the exoplanets: Radial Velocity, Transit Photometry, Microlensing, Astrometry, Direct Imaging, etc.
Before all of this, scientist had to find ways to prove their theories. Most of their time they have spent in giving the creative answers.
Science and creativity are very much connected when we speak about the development of science. Rationality and creativity always go together.
In order to create an idea that other people will consider useful, it is important to use creativity. As no one has the exact answer when it comes to science, the adventure is to research the unknown.
Answer:
W = - 5.01 10¹⁰ J
Explanation:
Work is defined by the expression
W = ∫ F.dr
Where the blacks indicate vectors, in the case the force is radial and the distance is also radial, whereby the scalar producer is reduced to an ordinary product
W = ∫ F dr
W = G m₁m₂ ∫ 1 /r² dr
W = G m₁ m₂2(-1 / r)
We evaluate between the lower limits r = Re and upper r = ∞
W = G m₁m₂ (-1 / Re + 1 / ∞)
W = - G m₁ m₂ / Re
Let's calculate
W = - 6.67 10⁻¹¹ 800 5.98 10²⁴ / 6.37 10⁶
W = - 5.01 10¹⁰ J
The answer is A. Newton's third law of motion states that for every action, there is an equal and opposite reaction. A rocket exerts a large force on the gas that is in the rocket chamber (action). The gas thus exerts a large reaction force forward on the rocket (reaction). The large reaction force is called thrust.
Answer:
Of longitudinal waves
Explanation:
Depending on the direction of the oscillation, there are two types of waves:
- Transverse waves: in a transverse wave, the oscillations occur perpendicularly to the direction of propagation of the wave. Examples are electromagnetic waves.
- Longitudinal waves: in a longitudinal wave, the oscillations occur parallel to the direction of propagation of the wave. In such a wave, the oscillations are produced by alternating regions of higher density of particles, called compressions, and regions of lower density of particles, called rarefactions. Examples of longitudinal waves are sound waves.
