Answer:
5 N right
Explanation:
Fx = 9N-4N
Fx = 5N
Since we can define the x and y axis. We have x to the right as positive.
Answer:

Explanation:
To solve this equation we will have to consider that the bubble is filled with an Ideal Gas and as such we can use the Ideal Gas Law

Where
= Pressure
= Volume
= Moles
= Ideal Gas Constant
= Temperature
Now since we know that the value for the temperature and moles is constant we can simply use Boyles Law for the two states

Let us look at the two states
State 1 (at top)
Pressure = 
Volume = 
State 2 (at bottom)
Pressure = 
Where
= Density of liquid (1000 kg/m³)
= Acceleration due to gravity (9.8 m/s²)
= Height of liquid (0.200 m)
Pressure = 
Volume = 
Inputting these values into the Boyles Law

The first: alright, first: you draw the person in the elevator, then draw a red arrow, pointing downwards, beginning from his center of mass. This arrow is representing the gravitational force, Fg.
You can always calculate this right away, if you know his mass, by multiplying his weight in kg by the gravitational constant

let's do it for this case:

the unit of your fg will be in Newton [N]
so, first step solved, Fg is 637.65N
Fg is a field force by the way, and at the same time, the elevator is pushing up on him with 637.65N, so you draw another arrow pointing upwards, ending at the tip of the downwards arrow.
now let's calculate the force of the elevator

so you draw another arrow which is pointing downwards on him, because the elevator is accelating him upwards, making him heavier
the elevator force in this case is a contact force, because it only comes to existence while the two are touching, while Fg is the same everywhere
Answer:
in physics, a photon is a bundle of electromagnetic energy. It is the basic unit that makes up all light
Explanation: