The nitrogen fixation is the process of conversion of nitrogen gas into a usable form.
Answer: Option 3
<u>Explanation:
</u>
The nitrogen fixation is the process where the nitrogen gas present in air gets trapped and converted into ammonia or other nitrogenous compounds. This is the first step of nitrogen cycle.
The atmospheric nitrogen will get absorb in soil and gets converted to either ammonia which acts as nutrition for plants or other nitrogen related compounds which acts as fertilizers.
So, the nitrogen which get converted to usable stable form of nitrogen compounds can be used by plants, microorganisms and other organisms in the ecosystem.
In endothermic reactions energy in the form of heat is given
Because it helps the nail to enter an object
Answer: h = 3R
Explanation:
Using the law of conservation of energy,
Total energy at the beginning of the launch would be equal to total energy at any point.
kinetic energy + gravitational potential energy = constant
Initial energy of the projectile =
... (1)
where R is the radius of the Earth, M is the mass ofthe Earth, m is the mass of the projectile.
escape velocity, 
Total energy at height h above the Earth where speed of the projectile is half the escape velocity:
...(2)
(1)=(2)
⇒
⇒
⇒
⇒
⇒h = 3R
Thus, at height equal to thrice radius of Earth, the speed of the projectile would reduce to half of escape velocity.
The cart's force is only in reaction to the horse's force so it does not define direction of movement.