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3 years ago

A train left the station at 9:00am. The next stop was 629 km south. It

Physics

1 answer:

Aleks04 [339]3 years ago

3 0

Explanation:

We need to calculate the time it had travelled first:

9:00 to 12:00 = 3 hours.

12:00 to 2:00 = 2 hours

Total travel time = 5 hours.

The formula for speed is distance ÷ time (Hence, the unit for speed is m/s, kph, mph, etc.)

= 629km ÷ 5 hours

= 125.8 km/hour ~ 125.8kph

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A 10.0 L tank contains 0.329 kg of helium at 28.0 ∘C. The molar mass of helium is 4.00 g/mol . Part A How many moles of helium a

nadya68 [22]

Answer:

82.25 moles of He

Explanation:

From the question given above, the following data were obtained:

Volume (V) = 10 L

Mass of He = 0.329 Kg

Temperature (T) = 28.0 °C

Molar mass of He = 4 g/mol

Mole of He =?

Next, we shall convert 0.329 Kg of He to g. This can be obtained as follow:

1 Kg = 1000 g

Therefore,

0.329 Kg = 0.329 Kg × 1000 g / 1 Kg

0.329 Kg = 329 g

Thus, 0.329 Kg is equivalent to 329 g.

Finally, we shall determine the number of mole of He in the tank. This can be obtained as illustrated below:

Mass of He = 329 g

Molar mass of He = 4 g/mol

Mole of He =?

Mole = mass / molar mass

Mole of He = 329 / 4

Mole of He = 82.25 moles

Therefore, there are 82.25 moles of He in the tank.

8 0

3 years ago

Calculate the current through a 3.0 Ď‰ resistor with a voltage of 9.0 v across it.

gulaghasi [49]

Answer: 3 A

Explanation:

According to<u> Ohm's law</u>:

$V=R.I$

Where:

$V=9 V$ is the voltage

$R=3\Omega$ is the resistance of the resistor

$I$ is the electric current (the value we want to find)

Isolating $I$ :

$I=\frac{V}{R}$

$I=\frac{9 V}{3\Omega}$

Finally:

$I=3 A$

7 0

3 years ago

The velocity of an object is the _____ of the object

katovenus [111]

D. Speed and direction, this is because velocity is a vector quantity so has a magnitude and direction assigned to it because it is the rate of change of displacement.

6 0

3 years ago

If a series circuit contains a 12-V battery, a 6-ohm resistor, and a 4-ohm resistor, what is the current in the circuit?

Shalnov [3]

In a series circuit the total current is the same throughout resistors and so:

$I_{total}=I_1=I_2$

The voltage is distributed throughout the resistors and so:

$V_{total}=V_1+V_2$

and the total resistance can be calculated by adding up the resistors resistance:

$R_{total}=R_1+R_2$

First thing is to calculate the total resistance and so:

$R_{total}=6\Omega + 4\Omega = 10\Omega$

And by Omh's law V=IR we have:

$V_{total}=I_{total}R_{total}\\\\I_{total}=\frac{V_{total}}{R_{total}}= \frac{12V}{10\Omega} =1.2A$

And so the total current of the circuit is 1.2 amps i.e. 1.2 A.

6 0

3 years ago

Read 2 more answers

A ray of light passes from air into a block of clear plastic. How does the angle of incidence in the air compare to the angle of

andre [41]

Answer:

The angle of incidence is greater than the angle of refraction

Explanation:

Refraction occurs when a light wave passes through the boundary between two mediums.

When a ray of light is refracted, it changes speed and direction, according to Snell's Law:

$n_1 sin \theta_1 = n_2 sin \theta_2$

where :

$n_1$ is the index of refraction of the 1st medium

$n_2$ is the index of refraction of the 2nd medium

$\theta_1$ is the angle of incidence (the angle between the incident ray and the normal to the boundary)

$\theta_2$ is the angle of refraction (the angle between the refracted ray and the normal to the boundary)

In this problem, we have a ray of light passing from air into clear plastic. We have:

$n_1=1.00$ (index of refraction of air)

$n_2=1.50$ approx. (index of refraction in clear plastic)

Snell's Law can be rewritten as

$sin \theta_2 =\frac{n_1}{n_2}sin \theta_1$

And since $n_2>n_1$ , we have

$\frac{n_1}{n_2}$

And so

$\theta_2$

Which means that

The angle of incidence is greater than the angle of refraction

6 0

3 years ago