17. 1 micrometer (1 µm) equals:

Hiaaa I need help pwease" concerning the planetary orbits why was Copernicus somewhat inaccurate?"

Yuki888 [10]

Copernicus's heliocentric theory stated that the planets orbited in perfectly circular orbits. In reality, they are shaped like ellipses (ovals).

4 0

3 years ago

What happens to the speed of an object when dropped at free fall

dedylja [7]

If it's not falling through air, water, smoke, or anything else,
and gravity is the only force on it, then its speed increases
at a constant rate ... 9.8 meters per second for every second
it falls. (That's the number on Earth. It's different in other places.)

3 0

4 years ago

Consider a very low (zero) friction, 5.0 kg skateboard on a ramp at an angle of 15 degrees to the horizontal. What would be the

malfutka [58]

You need to use trigonometry to work this one out. The components of the force are needed. it is a vector, so work out the unbalanced force using trig. you know that the force pulling the 5kg skateboard down is going to be 9.8 * 5 = 49N. As you have the angle it is on, and 49 is the vertical component, you can use Sin(X) = Op/Hyp where x= 15 degress, the opposite is the vertical component (49N) and the hyp is the unbalanced force - which is 79.35. I think. Somebody plz double check me on that one though :P

8 0

3 years ago

A fire hose 5 centimeters in diameter is used to fill a 225-liter bucket. If it takes 15 seconds to fill the bucket, what is the

Vika [28.1K]

I believe you ask about speed at the end of the hose:

The volume of the bucket is 225 liters which is equal to 225 $dm^{3}$ .
$V=225dm^{3}$
Hose's cross section can be counted with the typical circle's area formula (with diameter instead of radius, that's why you've got a fraction):
$A=3,14*\frac{d^{2}}{4}}=0,19625dm^{2}$

$225dm^{3}$ are filled within 15 second.

As the bucket is being filled you can say that it's volume is the volume of the water that flowed out of the hose, then:
$V=A*h$
The speed of the water can be counted with equation:
$v=\frac{h}{t}$
After extracting h from the volume's equation you get:
$v=\frac{V}{A*t}$
When you count the fraction you get the answer:
$v=76,43\frac{dm}{s}=0,7643\frac{m}{s}$

4 0

3 years ago

Please help me Calculate the total energy stored in the capacitor

Neko [114]

La fórmula: P = W/t ó W = P x t. donde:

P = potencia

W = trabajo

t = tiempo

Otra fórmula de potencia es: P= I x V

Proceso de carga de un capacitor - condensador

Una fórmula muy importante que también hay que tener en cuenta es: V = q/C que indica que el voltaje es proporcional a la carga que hay en un condensador.

De la fórmula de potencia P= I x V y considerando que la corriente es constante (corriente continua), entonces la potencia es proporcional al voltaje. Si el voltaje aumenta en forma lineal, la potencia aumentará igual. Ver el siguiente diagrama.

Como la potencia varía en función del tiempo, no se puede aplicar la fórmula W = P x t, para calcular la energía transferida. Pero observando el gráfico, se ve que esta energía se puede determinar midiendo el área bajo la curva de la figura.

Energía Almacenada en un Condensador - Capacitor

El área bajo la curva es igual a la mitad de la potencia en el momento “t”, multiplicada por “t”.

Entonces: W = (P x t) / 2. Pero se sabe que P = V x I. Si se reemplaza esta última fórmula en la anterior se obtiene: W = (V x I x t) / 2, y como I x t = CV = Q, entonces para saber cuanta energía (W) hay en un condensador usamos una de las siguientes fórmulas:

W = (CV2/2) julios

W = (QV/2) julios

W = (Q2/2C) julios

, donde:

W = Trabajo (Energía) en julios

C = Capacidad en faradios

V = voltaje en voltios en los extremos del condensador

Q = carga del condensador

3 0

3 years ago

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