The water cycle starts with evaporation. It is a process where water at the surface turns into water vapors. Water absorbs heat energy from the sun and turns into vapors. Water bodies like the oceans, the seas, the lakes, and the river bodies are the main source of evaporation. Through evaporation water moves from hydrosphere to atmosphere.
<h2>Answer: Venus</h2>
Galileo was the first to use the telescope to observe the heavens, mainly observing the Moon, the Sun with its sunspots, Jupiter with its moons and Venus (in the early 1600s).
In the case of Venus, he observed that it presented phases (such as those of the moon) together with a variation in size; observations that are only compatible with the fact that Venus rotates around the Sun and not around Earth.
This is because Venus presented its smaller size when it is in full phase and the largest size when it is in the new one, when it is between the Sun and the Earth.
These images along with other discoveries were presented to the Catholic Church (which supported the <u>geocentric theory</u> for that time) as a proof that completely refutes Ptolemy's geocentric system and affirms <u>Copernicus' heliocentric theory.</u>
Ways to increase friction
- increase the area of contact
- increase the roughness of the contact materials
- dry up or take away any lubricant
- increase the pressure on the contact
As per the question the total distance is given as 4 km.
We are asked to calculate the average speed.
The time taken by the body to travel each kilometre are 5.9 min,6.2 min.,6.3min. and 6 min. respectively.
The average speed of a body is defined as the ratio of total distance travelled by the body to the total time.
Mathematically the average speed is written as _
V= Total distance/Total time
i.e V = S/T
Where S is the total distance travelled and T is the total time
Here total distance (S)= 4 km
The total time T= (5.9+6.2 +6.3+ 6.0 )minutes
=24.4 min.
Hence average speed V = 4 km/24.4 min
= 0.16 km/min.
Hence the correct option is A .
