Dr Tony Allision hypothesize that the sickle cell disease is connected with malaria. The disease carried by the mosquito is more common in coastal area and near Lake Victoria while it is less common in the highlands. He made a further hypothesis that sickle cell disease is common in areas where malaria is also common.
B) It’s material moves due to convection currents.
Answer:
1.909 m
Explanation:
Length of fence = 12 m
r = Radius of circle made by the provided fence
Cirumference of a circle is given by
The circumference of the circle will be equal to the length of the fence
The radius of the fence is 1.909 m
The velocity of the ferry relative to the current is 4.5 m/s.
<h3>Relative velocity</h3>
- Relative velocity is the velocity of a body as observed from the reference point of another body either stationary or in motion.
Since the river is flowing parallel to the shore and the ferry is moving perpendicular to the shore, their velocities are at right angles to each other.
The two velocities form a right angled-triangle of sides 2, 4 and a hypotenuse which gives the relative velocity of the ferry to the current.
Using Pythagoras rule:
- Let c be the hypotenuse
- a = velocity of the ferry, and
- b = the velocity of the current, and
c² = 4² + 2²
c² = 16 + 4
c = 20
c = √20
c = 4.47 m/s
c ≈ 4.5 m/s
Therefore, the velocity of the ferry relative to the current is 4.5 m/s.
Learn more about relative velocity and Pythagoras rule at: brainly.com/question/25617868
Answer:
Advantage:
Apparent solar time gives the exact location of sun in the sky according to your precise location.
Disadvantage:
As the apparent solar time changes with the change in longitude. It is very difficult to track these changes in longitude. Hence, it is almost impossible to make plan for events.
Improvement in situation:
Situation can be improved using mean solar time because due to this people living in the longitude band agree upon a standard time. In this way, it is easy to plan for events.
