An airplane is at rest on a runway. It accelerates at 10 m/s2 for 15 seconds. How fast is it now traveling?

If temp. gets cold resistance in thermostat increases so voltage across it increases AND LED lights brighter. I understand every

Valentin [98]

Normally, when something gets colder, its electrical resistance gets smaller. This is true of component-A in the drawing ... a simple resistor.

The component labeled 'B' has a strange and unusual symbol, and it's not a simple resistor. It's a "thermistor". The word "thermal" always has something to do with heat, and "thermistor" comes from "thermal resistor. These things can be manufactured either way ... using different materials, a thermistor can be manufactured so that its resistance goes UP, or goes DOWN, or doesn'tchange when it gets colder. I'm pretty sure that's what's going on here.

When this circuit gets colder, resistance-A gets smaller, but resistance-B either gets bigger OR doesn't change. Either way, the voltage across B increases. Since the LED is connected directly across B, the current through it depends on that voltage, so the LED gets more current, and becomes brighter, when A and B both get colder.

This circuit could actually be a very useful device. If you took out the LED and put a voltmeter in its place, then the reading on the voltmeter would tell you the temperature of wherever you put the two components A and B.

5 0

3 years ago

It is night. Someone who is 4 feet tall is walking away from a street light at a rate of 8 feet per second. The street light is

KiRa [710]

Answer: 4 ft/s

Explanation:

Given

height of man $=4 ft$

speed of person $v=8 ft/s$

height if street light $=12 ft$

Let x be the distance between person and street light and y be the length of his shadow

From diagram

as the two triangle ADE and ABC are similar therefore we can say that

$\frac{4}{12}=\frac{y}{x+y}$

$\frac{1}{3}=\frac{y}{x+y}$

$x+y=3y$

$x=2y$

differentiate above Equation w.r.t time we get

$\frac{\mathrm{d} x}{\mathrm{d} t}=2\frac{\mathrm{d} y}{\mathrm{d} t}$

$\frac{\mathrm{d} y}{\mathrm{d} t}=\frac{8}{2}=4 ft/s$

6 0

3 years ago

Trace the path of a ray emitted from the tip of the object toward the focal point of the mirror and then the reflected ray that

Crazy boy [7]

Answer: find the attached files for the answer

Explanation:

The reflected ray appears to have originated from the focal point. We should actually draw a vector from the focal point through the point where the incident ray hits the mirror but we shorten the vector so that its starting point is on the mirror, without changing its angle.

Please find the attached files for the solution

5 0

3 years ago

An "energy bar" contains 26 g of carbohydrates. For the steps and strategies involved in solving a similar problem, you may view

masha68 [24]

To solve this problem we will apply the definition of Power and Speed. In turn, we will consider that one gram of carbohydrate, according to numerous scientific studies, contributes around 17kJ of energy. Therefore, if this were true, the total energy of 26 grams would be

$E = (26)(17000) = 4.42*10^5J$

Power can be described as the amount of energy applied at a given time, that is,

$P = \frac{E}{t} \rightarrow t = \frac{E}{P}$

$t = \frac{4.42*10^5}{380}$

$t = 1.16*10^3s$

The speed is described as the distance traveled in a certain time, and its units in international system is m / s, converting and replacing we will have

$v = 5km/h(\frac{1000m}{1km})(\frac{1h}{3600s})$

$v = 1.388m/s$

Now,

$v = \frac{d}{t} \rightarrow d = vt$

The distance is,

$d = vt$

$d = (1.388)(1.16*10^3)$

$d = 1610.08m$

Therefore the distance walked is 1610.08m

7 0

3 years ago

What happens to the appearance of an object as it gets hotter?

lana [24]

Answer:

Explanation:

When an object is heated then it becomes brighter and bluish compared to the initial condition. This happens because when an object is given heat then the electron in the ground state gets excited and reaches some higher state. After reaching a higher state electron make the transition to lower state and simultaneously exhibit the color which is visible with naked eyes.

3 0

3 years ago

An airplane is at rest on a runway. It accelerates at 10 m/s2 for 15 seconds. How fast is it now traveling?​

An airplane is at rest on a runway. It accelerates at 10 m/s2 for 15 seconds. How fast is it now traveling?