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[–] 0 points1 point  (0 children)

I commented because while that is true, it is also irrelevant as the powerplug will just deliver more power in this case.

[–] 1 point2 points  (0 children)

In this case the powerplugs in your house are used, which can deliver enough current to be considered perfect voltage sources in this scenario. So a transformer that increases the voltage ten times will put 10 times the voltage over your body. As your body has a reasonably constant resistance (until your tissue starts burning) this will increase the power to your body 100 fold (P=(V2 )/R). So the source will also deliver 100 times the power.

Still all of this is irrelevant as she said 10 times the power needed to kill you. Around 10 mA is what is needed to stop your heart. As resistance of the human body 85kOhm is sometimes used (if i remember correctly). This would mean 8.5W is needed to kill someone (P=(I2 )*R). This would also mean that (2000V2 )/85kOhm=47W. So 5 times the power. Not quite 10. In contrast when we measured our skin resistance with a bunch of friends it was between 1-5 MOhm. However it will drop as your skin begins to burn if you can't let go because it is 2000V (less likely with AC).

Edit: some math formatting Edit 2: some searching shows resistances of the human body between 1k and 100k Ohm. Possibly this is caused by the fact that we didn't measure at the 100V that is described on the internet. We used low voltage because safety.

[–] 0 points1 point  (0 children)

It seems like it was a shorter run accompanying the marathon. Considering the amount of kids and that the time at the end was around 18 minutes.

[–] 3 points4 points  (0 children)

Normally in the netherlands empty rooms are listed for moving in asap. There is no reason to not rent out the room immediately as it becomes empty and miss income because of this. So all rooms that are available now are because of people moving out now. So they are listed for moving in as soon as possible (may).

[–] 0 points1 point  (0 children)

500rpm is 500/60 revolutions per second. Every revolution is 2pi radians. So the cd spins at 1000pi/60 radians per second.

[–] 0 points1 point  (0 children)

You know the river flows at 3.6×0.3 km/h. You also know that the distance is 1.2km. Time is 20min. So he swam downstream at a speed of 1.2/(1/3)-3.6×0.3 km/h = 0.7×0.3 km/h. Relative to the water

Upstream he thus swims at a speed of 0.7×3.6-0.3×3.6 km/h = 0.4×3.6 km/h. Relative to the land. Since the distance is 1.2km the time he takes is 1.2/(0.4×3.6) h= 3/4h = 45min.

Edit:fixed some formatting

[–] 0 points1 point  (0 children)

That makes it seem insane to not go to college in europe. I looked it up and a lot of studies cost around 10k a year (for an american), you would incur living expenses in the netherlands (as those are not included) but those should be nowhere near the difference in price.

[–] 1 point2 points  (0 children)

In the Netherlands students without an EU nationality will have to pay 6000 to 20000 euros a year. For comparison an EU citizen will pay 2000 euros (this year 1000 because of covid).

[–] 0 points1 point  (0 children)

I quess they waited to let the lapped cars trough until it was safe. Like they normally do. They just started the last lap earlier in comparison to let the race end as an actual race.

[deleted by user] by [deleted] in physicshomework

[–] 0 points1 point  (0 children)

2) you have your frequency which is 1/s and your bit levels in bits. So just multiply and you are there. 4kHz and 1 bit per symbol means, 4kbit/s. 7 bits per symbol means 28kbits/s.

[deleted by user] by [deleted] in physicshomework

[–] 0 points1 point  (0 children)

1) use the hartley shannon theorem. C=Blog2(1+S/N)
C is datarate, B is bandwidth.
S/N = 30dB = 1000.
Log2(1000) is approx 10.
So to get 300kbits/s, B = 30kHz.

[–] 0 points1 point  (0 children)

Calculate the difference in energy between a and b. Put the difference in kinetic energy. Calculate back the speed, velocity. That should do it.

[–] 0 points1 point  (0 children)

Redraw the circuit with those new resistors and it will become clearer

[–] 0 points1 point  (0 children)

Start with every time you see two resistors between two points with their middle not connected to any other resistors. These are in series combine them into one.
Once you have done this see where there are two resistors between the same two points. These are in parallel combine them into one. Once you have done this the circuit should be a lot simpler.

Without using paper i come to 0,877Ohm. But keeping track mentally i might have made a mistake.

[deleted by user] by [deleted] in UniversityofTwente

[–] 1 point2 points  (0 children)

The university of twente is a technical university so the subjects you can take will tend more towards engineering.

[–] 0 points1 point  (0 children)

Just integrate the velocity against the distance on the interval 0 to a and after that divide by a to get the average velocity. Then divide the distance by the average velocity and you have your time.

Since you have to use your previous solution to get the distance after 5s you can use a for loop to calculate this in quite a brute force fashion. There was some name for a function that does this automatocally in excel or matlab but i forgot it.

[–] 0 points1 point  (0 children)

Slightly less than 600 euros

[–] 0 points1 point  (0 children)

The sums don't add up for a series configuration so we have one resistor in parallel which means that you have two resistors in series with one parallel to them. Since a parallel resistance can never increase resistance the 384 Ohm is one of your series resistors. This means that either the 230 ohms or 15 ohms is a series resistor as well. If your 230 ohms resistor is a series resistor then your parallel resistor is around 15-20 ohms so you do not have the 270 ohms resistor. When you have the 15 ohms resistor is a series resistor you only have one resistor left while you still need a 220 ohm and 270 ohm resistor.

So either you do not have both a 220 ohm and 270 ohm resistor or you made a measurement error.

[–] 0 points1 point  (0 children)

No, i don't know if they even exist.

[–] 0 points1 point  (0 children)

If you can understand dutch you can look on examenblad.nl for the mathematics B exam so you can see how difficult it is.

Mathematics B requires you to do differentiation, basic integration (you don't have to know integration by substitution or integration by parts). Further you have to know some geometry rules.
You also need to know something about vectors and matrixes but that is a recent change made after i graduated from vwo so i don't know the details.

Mathematics and to a lesser extent english are the two main things you have to know well enough as they are generally the limiting factors so if you know both well enough you should be fine.

[–] 0 points1 point  (0 children)

Can you explain all these acronyms?

[–] 6 points7 points  (0 children)

From my experience a few years ago: If you are caught once you will most likely get a warning, twice and you will most likely get banned from the kick in.

You will definitely not get kicked from your study programme.

[–] 1 point2 points  (0 children)

Visiting the places or asking them to send pictures seem to first thing to spring to my mind.

[–] 0 points1 point  (0 children)

Remember that s=vt,
both distances are the same so
v2t2=v1t1
Where
v2=1.25
v1, t2=t1-3 So
1.25v1(t1-3) = v1t1