Answer:
red shift, indicating that the universe is expanding
Explanation:
Doppler effect occurs when a source of a wave (e.g. light, or sound waves) moves relative to an observer; as a result of this relative motion, the wavelength of the wave appears lengthened/shortened to the observer. Two situations can occur:
- The source of the wave is moving towards the observer - in this case, the wavelength of the wave becomes shorter. If the wave is visible light, such as the light emitted by distant galaxies, this means that the wavelength of the light shifts towards the blue-end of the spectrum (blue-shift)
- The source of the wave is moving away from the observer - in this case, the wavelength of the wave becomes longer. If the wave is visible light, such as the light emitted by distant galaxies, this means that the wavelength of the light shifts towards the red-end of the spectrum (red-shift)
In our universe, we observe a red-shift for all the distant galaxies: this means that these galaxies are moving away from us, so this is an indication that the universe is expanding.
Answer:
0.423m
Explanation:
Conversion to metric unit
d = 4.8 cm = 0.048m
Let water density be 
Let gravitational acceleration g = 9.8 m/s2
Let x (m) be the length that the spring is stretched in equilibrium, x is also the length of the cylinder that is submerged in water since originally at a non-stretching position, the cylinder barely touches the water surface.
Now that the system is in equilibrium, the spring force and buoyancy force must equal to the gravity force of the cylinder. We have the following force equation:

Where
N is the spring force,
is the buoyancy force, which equals to the weight
of the water displaced by the submerged portion of the cylinder, which is the product of water density
, submerged volume
and gravitational constant g. W = mg is the weight of the metal cylinder.

The submerged volume would be the product of cross-section area and the submerged length x

Plug that into our force equation and we have



Resistance = Voltage/Current
Wattage = Voltage * Current
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That means the current drawn by the lamp is equal to 100 watts divided by 210 volts.
Resistance =
Answer:
A.
Explanation:
A man using a microwave to boil water
Here the weight is hung from the thread inside the ceiling of train
now the FBD of train is analysed
We can say


now by ratio of two equations we have

this shows that train must be in accelerating condition due to which the thread is making an angle with the vertical
now we will have
2 The train is not an inertial frame of reference.
Since train is accelerating so it must be non inertial frame
5 The train may be moving at a constant speed in a circle.
Since its moving in circle so it is in accelerating condition
8 The train must be accelerating.