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3 years ago

Day and night are caused by

Physics

1 answer:

JulijaS [17]3 years ago

4 0

Answer:

Explanation:

How is the rotation of the earth responsible for causing day and night?

We get day and night because the Earth spins (or rotates) on an imaginary line called its axis and different parts of the planet are facing towards the Sun or away from it. It takes 24 hours for the world to turn all the way around, and we call this a day.

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A Micro –Hydro turbine generator is accelerating uniformly from an angular velocity of 610 rpm to its operating angular velocity

Salsk061 [2.6K]

Answer:

Angular displacement of the turbine is 234.62 radian

Explanation:

initial angular speed of the turbine is

$\omega_i = 2\pi f_1$

$\omega_1 = 2\pi(\frac{610}{60})$

$\omega_1 = 63.88 rad/s$

similarly final angular speed is given as

$\omega_f = 2\pi f_2$

$\omega_2 = 2\pi(\frac{837}{60})$

$\omega_2 = 87.65 rad/s$

angular acceleration of the turbine is given as

$\alpha = 5.9 rad/s^2$

now we have to find the angular displacement is given as

$\theta = \omega t + \frac{1}{2}\alpha t^2$

$\theta = (63.88)(3.2) + (\frac{1}{2})(5.9)(3.2^2)$

$\theta = 234.62 radian$

3 0

3 years ago

A spaceship orbiting earth flies to the moon. How is the gravitational force pulling on the spaceship related to the distance th

____ [38]

The correct answer is "As the distance from the earth increases, the gravitational pull on the spaceship would decrease."

In fact, the gravitational force (attractive) exerted by the Earth on the spaceship is given by
$F=G \frac{Mm}{d^2}$
where G is the gravitational constant, M the Earth's mass, m the mass of the spaceship and d the distance of the spaceship from the Earth. As we can see from the formula, as the distance d between the spaceship and the Earth increases, the gravitational force F decreases, so answer D) is the correct one.

3 0

3 years ago

A container in the shape of a cube 10.0 cm on each edge contains air (with equivalent molar mass 28.9 g/mol) at atmospheric pres

Vikentia [17]

Answer:

a) m = 1.174 grams

b) F_g = 0.01151 N

c) F_c = 1013 N

Explanation:

Given:

- The length of a cube L = 10.0 cm

- The molar mass of air M = 28.9 g/mol

- Pressure of air P = 101.3 KPa

- Temperature of air T = 300 K

- Universal Gas constant R = 8.314 J/kgK

Find:

(a) the mass of the gas

(b) the gravitational force exerted on it

(d) Why does such a small sample exert such a great force? (6%)

Solution:

- Compute the volume of the cube:

V = L^3 = 0.1^3 = 0.001 m^3

- Use Ideal gas law equation and compute number of moles of air n:

P*V = n*R*T

n = P*V / R*T

n = 101.3*10^3 * 0.001 / 8.314*300

n = 0.04061 moles

- Compute the mass of the gas:

m = n*M

m = 0.04061*28.9

m = 1.174 grams

- The gravitational force exerted on the mass of gas is due to its weight:

F_g = m*g

F_g = 1.174*9.81*10^-3

F_g = 0.01151 N

- The force exerted on each face of cube is due its surface area:

F_c = P*A

F_c = (101.3*10^3)*(0.1)^2

F_c = 1013 N

- The molecules of a gas have high kinetic energy; hence, high momentum. When they collide with the walls they transfer momentum per unit time as force. Higher the velocity of the particles higher the momentum higher the force exerted.

4 0

3 years ago

What is the time required for an object starting from rest.

sashaice [31]

Time required for what?

6 0

2 years ago

3. Do you have an issue with the NSA monitoring citizens’ phone calls, text messages, emails, etc.?

goblinko [34]

<span> If You Have Nothing to Hide, You Have Nothing to Fear</span>

8 0

3 years ago