Well depending on the speed of both of those things is were the rock will be placed and it also determines how fast can an environment change
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Answer: W =
J
Explanation: Since the potassium ion is at the outside membrane of a cell and the potential here is lower than the potential inside the cell, the transport will need work to happen.
The work to transport an ion from a lower potential side to a higher potential side is calculated by

q is charge;
ΔV is the potential difference;
Potassium ion has +1 charge, which means:
p =
C
To determine work in joules, potential has to be in Volts, so:

Then, work is


To move a potassium ion from the exterior to the interior of the cell, it is required
J of energy.
Answer:
We have learned that refraction occurs as light passes across the boundary between two media. Refraction is merely one of several possible boundary behaviors by which a light wave could behave when it encounters a new medium or an obstacle in its path.
Answer:
The velocity of mass 2m is 
Explanation:
From the question w are told that
The mass of the billiard ball A is =m
The initial speed of the billiard ball A =
=1 m/s
The mass of the billiard ball B is = 2 m
The initial speed of the billiard ball B = 0
Let the final speed of the billiard ball A = 
Let The finial speed of the billiard ball B = 
According to the law of conservation of Energy

Substituting values

Multiplying through by 

According to the law of conservation of Momentum

Substituting values

Multiplying through by 

making
subject of the equation 2

Substituting this into equation 1




Multiplying through by 



Answer:
b) Gravity
Explanation:
Gravity acts all of the time, when you apply force to a projectile it has to be more than the forces of the gravity and air resistance together so the projectile can move, when the rock is at the top of its trajectory the force that you applied at the beginning is getting lost, so the other forces (air resistance and gravity) make the rock fall to the floor.