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4 years ago

Once a satelite has entered a stable orbit round earth why does it not need fuel?

1 answer:

5 0

For the same reason that the Earth doesn't need any fuel to keep
orbiting the sun, and the moon doesn't need any fuel to keep
orbiting the Earth..

Here's something to think about: A satellite in a perfectly circular
orbit always stays at the same distance from the Earth, so it never
moves in the direction of the gravitational force. The work that
gravity does on it is (force) x (distance) = zero, so the satellite's
energy never changes.

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An object of mass M oscillates on the end of a spring. To double the period, replace the object with one of mass: (a) 2M. (b)M/2

harkovskaia [24]

Answer:

Explanation:

The system is a loaded spring. The period of a loaded spring is given by

$T = 2\pi\sqrt{\dfrac{m}{k}}$

m is the mass and k is the spring constant.

It follows that, since k is constant,

$T\propto\sqrt{m}$

$\dfrac{T}{\sqrt{m}} = C$ where C represents a constant.

$\dfrac{T_1}{\sqrt{m_1}} = \dfrac{T_2}{\sqrt{m_2}}$

$m_2 = m_1\left(\dfrac{T_2}{T_1}\right)^2$

When the period is doubled, $T_2 = 2T_1$ .

$m_2 = m_1\left(\dfrac{2T_1}{T_1}\right)^2 = 4m_1$

Hence, the mass is replaced by 4M.

7 0

4 years ago

Find the Gravitational Potential at a point on the earth’s surface. Take mass of earth as 5.98 X 10 24 kg, its radius as 6.38 X

kherson [118]

Answer:

$-6.25 x 10^7 J/Kg\\\\$

Explanation:

The final answer is $-6.25 x 10^7 J/Kg\\\\$

5 0

3 years ago

The principle of conservation of energystates that energy is neither created nor destroyed. Which of thefollowing describes the

bezimeni [28]

Answer: the statement that describes the transformation of energy is statement B (The potential energy was turned into Albertine's kinetic energy, which was then converted into internal(thermal) energy.)

Explanation:

Law of conservation of energy states that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.

Throughout Albertine's journey, no energy was lost. Her potential energy was converted to kinetic energy and then to thermal energy of the body.

5 0

3 years ago

A ray of violet light has a wavelength of about 4.2×10−7 m. will exposure to violet light cause electrons to be emitted from ces

lesantik [10]

The wavelength of violet light is given as 4.2x10^-7 m and the speed of light is 3x10^8 m/sec

The equation relating between the frequency and the wavelength is as follows:
speed of light = wavelength x frequency

Substitute with the givens in the above equation to get the frequency of violet light as follows:
frequency = (3 x 10^8) / (4.2 x 10^-7) = 7.14285 x 10^14 Hz

The threshold frequency of cesium is 9.39x10^14 Hz.
Since the frequency of violet light is less than the threshold frequency of cesium, therefore, the exposure to violet light won't cause electrons to be emitted from cesium.

7 0

3 years ago

An electric heater is used to boil small amounts of water and consists of a 18-Ω coil that is immersed directly in the water. It

Licemer1 [7]

Answer:

Is required 5.26 min to raise the temperature.

Explanation:

R= 18 ohms

V= 120 volts

m= 0.71 kg

C= 4186 J/kg °C

T1= 15°C

T2= 100 °C

Q= m * C * (T2-T1)

Q= 252.62 *10³ J

V/R= I

I= 6.66 A

P= I² * R

P= 800 W = 800 J/s

P= Q/t

t= Q/P

t= 315.77 s = 5.26 min

8 0

3 years ago