1). Calculate how long it takes an object to fall 4,000 m after it's dropped. (Use D = (1/2) (g) (T²) . D is 4,000 m. g = 9.8 m/s². Find T .)
2). Calculate how far the object will move HORIZONTALLY in that length of time, if it's moving at 75 m/s. (Distance = (75 m/s) x (time) . )
The resultant force on the animal = Resultant mass * total acceleration
F = 0.2 * 2.5 to the right
F = 0.5 to the right.
As, girl exerting a force of 3.5 N & it's not mentioned that she is in right or left, so the force exerting by boy would be either:
3.5-0.5 = 3 OR 3.5+0.5 = 4
If boy exerting a greater force then, answer will be 4 N & if girl exerting a greater force the, answer will be 3 N
Hope this helps!
Answer:

Explanation:
For this case we have the following info given:
Number of Na+ ions 
Each ion have a charge of +e and the crage of the electron is 
The time is given
if we convert this into seconds we got:

Now we can use the following formula given from the current passing thourhg a meter of nerve axon given by:

Where N represent the number of ions, e the charge of the electron and Q the total charge
If we replace on this case we have this:

And from the general definition of current we know that:

And since we know the total charge Q and the time we can replace:

The current during the inflow charge in the meter axon for this case is 
A synthesis reaction forms one product from two reactants.
It has the general form A + X ⇒ AX.
I think you can google this because I really don’t know the answer I’m so sorry