Physics, 16.10.2019 00:30 deonharris18

1. suppose a tank filled with water has a liquid column with a height of 10 meters. if the area is 2 square meters (m²), what's the force of gravity acting on the column of water?
2. if a total force exerted by water in a container with a bottom area of 3 square meters is 900 newtons, what is the water pressure at the bottom of the container?
3. a tank with a flat bottom is filled with water to a height of 7.5 meters. what's the pressure at any point at the bottom of the tank? (you can ignore atmospheric pressure in your calculations.)
4. in a tank full of water, the pressure on a surface 2 meters below the water level is 1.5 kpa. what's the pressure on a surface 6 meters below the water level?
5. a piston above a liquid in a closed container has an area of 0.75 m², and the piston carries a load of 200 kg. what will be the external pressure on the upper surface of the liquid?

Answers: 2

Show answers

Answers

Answer from: tanabugg

Answers:

1. Firstly, we have to define that Pressure is Force applied per unit area . It is mathematically expressed as follows:

$P=\frac{F}{A}$ (1)

The unit of P is Pascal (Pa) which is equivalent to $\frac{kg}{ms^{2}}$ and also equivalent to $\frac{N}{m^{2} }$

There is also another expression of the Pressure in which it is dependent on the density of the liquid, the height of the container and the gravity force :

P=d*h*g (2)

In this problem the liquid is water, and its known density is approximately:

$d=1000kg/m^{3}$

So, we have to substitute the values in equation (2) to obtain the pressure (Being careful with the units):

$P=1000\frac{kg}{m^{3}}*10m*9.8\frac{m}{s^{2}}$

P=98000Pa

Then, we have to substitute this value in equation (1) and clear :

F=P*A

Finally:

F=196000N

2. For this problem, we will use equation (1) to find the Pressure. We already know the area and the force exerted by water in the container :

$P=\frac{F}{A}=\frac{900N}{3m^{2}}$

P=300Pa

3. In this case, equation (2) is the perfect way to find the hydrostatic pressure at any point at the bottom of the tank (be careful with the units):

P=d*h*g

$P=1000\frac{kg}{m^{3}}*7.5m*9.8\frac{m}{s^{2}}$

P=73500Pa

4. In this case, it's important to know that in fluids (in this case the water) the higher the fluid is, the lower the pressure. Then, if $P_{1}$ and $P_{2}$ are the respective pressures at the heights $h_{1}$ and $h_{2}$ , and knowing that the water density and the gravity force in this case are constants, we can use the following expression to solve this problem:

$P_{2}- P_{1} =d*g(h_{2}- h_{1})$ (3)

Where:

$P_{1}=1.5 kPa$ at $h_{1}=2m$

Note that 1kPa=1*1000 Pa

And $P_{2}=?$ is unknown at a given height $h_{2}=6m$

Then, we have to substitute the values in equation (3) to find $P_{2}$ :

$P_{2}-1500Pa=1000\frac{kg}{m^{3}}*9.8\frac{m}{s^{2}} (6m-2m)$

Finally: $P_{2} =40700Pa$

5. In this case we have the area $A=0.75m^{2}$ and the mass of the piston m=200kg , and we need to know the pressure .

We will use equation (1):

$P=\frac{F}{A}$

But, do you remember that above we stated that pressure is the force applied over an area?

Well, in this case we will use the following equation, in which the gravity force and the mass of a body are involved, to find :

$F=m*g=200kg*9.8\frac{m}{s^{2}}$

Then:

F=1960N

Now we can finally calculate :

$P=\frac{1960N}{0.75m^{2}}$

P=2613.33Pa

Answer from: Quest

force tends to be low and long diustance masses are high

Answer from: Quest

The magnets are probably damaged or there not strong enough to attached to the refrigerator

Other questions on the subject: Physics

Physics, 20.06.2019 18:02, cooljazzy1234

Rebekah has a table that has a mass of 21.7 kg. what is the weight of the table? a. 6 n b. 31.5 n c. 9.8 n d. 212.66 n

Answers: 3

continue

Physics, 21.06.2019 22:30, nuhaminbruk

Ann walks 80 meters on a straight line 33 ∘ north of east starting at point 1. draw ann's path. represent ann's walk with a vector of length 80 meters. draw the vector starting at point 1. the length given in the display is in meters.

Answers: 1

continue

Physics, 22.06.2019 01:00, winnie45

Red’s momentum vector before the collision is green’s momentum vector after the collision. question 1 options: shorter than longer than equal to question 2 (1 point) saved since green bounces off red, this must be an collision. question 2 options: explosion inelastic elastic question 3 (1 point) saved red transfers of its momentum to green during the collision. question 3 options: little all most none question 4 (4 points) why does red transfer all its momentum to green? back up your answer with information from the simulation. write at least 2 sentences. question 4 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. question 5 (1 point) now make red much heavier than green. answer the questions below to describe how both red and green behave after the collision. you might want to play the sim multiple times. click on restart or return balls to start over. to see numbers, check the show values box (inside the green box). red during the collision because it transferred some momentum to green. question 5 options: sped up kept the same velocity slowed down question 6 (1 point) green sped up during the collision as it question 6 options: lost momentum to red maintained a constant momentum. gained momentum from red question 7 (1 point) after the collision . . question 7 options: red bounced off green and went to the left. green moved to the right. both green and red stopped as they have lost all momentum. red stopped and green moved to the right. both green and red moved to the right. question 8 (4 points) only some of red’s momentum was transferred to green. why did this occur? back up your answer with information from the simulation. write at least 2 sentences. question 8 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. question 9 (1 point) now make red much lighter than green. answer the questions below to describe how both red and green behave after the collision. you might want to play the sim multiple times. click on restart or return balls to start over. to see numbers, check the show values box (inside the green box). which is true about the collision? question 9 options: green slowed down after the collision therefore it must have lost momentum. green sped up after the collision therefore it must have lost momentum. green sped up after the collision therefore it must have gained momentum. green slowed down after the collision therefore it must have gained momentum. question 10 (1 point) since green gained momentum, red had to have momentum because you cannot create or destroy momentum. question 10 options: lost kept the same amount of gained question 11 (1 point) since green was so much and harder to move, it caused red to bounce back to the left giving red . question 11 options: lighter. . . . negative heavier . . . . negative lighter. . . . positive heavier . . . . positive question 12 (4 points) now, click on more data at the bottom of the sim. play with different numbers for the masses and starting velocities. you can even make the starting velocities negative! tell me one thing you discovered by adjusting the speeds and masses. write at least 2 sentences. be specific and use words like velocity, momentum, mass, increased, decreased, etc. question 12 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. part 2: inelastic collisions question 13 (1 point) click on the "less data" box at the bottom of the sim. in the green box, slide the elasticity meter all the way to inelastic so there is 0% elasticity: make the masses whatever size suits you. make sure that green starts out with a velocity of 0 m/s – if you didn’t change this in the last step, you don’t need to do anything. push play and observe! true or false: when red and green collide, they stick together. question 13 options: true false question 14 (1 point) the velocity of red & green after the collision is the velocity that red started off with. question 14 options: larger than smaller than equal to

Answers: 1

continue

Physics, 22.06.2019 10:00, autumnskye1

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

Answers: 3

continue

You know the right answer?

1. suppose a tank filled with water has a liquid column with a height of 10 meters. if the area is 2...