Answer:

Explanation:
<u>Mechanical Force</u>
According to the second Newton's law, the net force F exerted by an external agent on an object of mass m is:
F = m.a
Where a is the acceleration of the object.
Assume we apply some given force F to an object of m1=1 Kg that produces an acceleration
, then:
F = m1.a1
The same force F is now applied to a second object m2=4 Kg that produces an acceleration a2, then:
F = m2.a2
Dividing both equations:

Solving for a2:

Substituting values:


If only that were true, you would see tidal power stations
all up and down every coast by now.
Human hair
Yield strength (MPa)
140-160
Ultimate tensile strength (MPa)
200-250
Hope that helps.
Answer: B. meteorites, UV rays
The earth's atmosphere plays an important role in shielding the space rocks and meteorites enters inside the earth due to collision with the celestial body. Due to high heat and pressure in the mesospheric layer of the atmosphere these meteorites burned up before reaching the biosphere or hydrosphere system of the earth. The UV rays are protected from entering into the earth atmosphere by the ozone layer present in the stratosphere of the atmosphere. Both meteorites and UV rays can negatively effect the human population. Therefore, the atmosphere is an agent which provides protection against them.