Answer:
A) The crossbeam is moving relative to the observer on the platform so the height appears contracted.
Explanation:
The observer on the train and the beam are in the same reference frame. That means observer on the train will measure the proper length of the beam not the contracted length . the observer is outside and the plank is in the moving system,it will appear to be moving.
Answer:
B.electromagnetic spectrum
Explanation:
Electromagnetic spectrum is used to describe all of the wavelengths of light waves.Generally wavelength of the wave is denoted by λ.
Wavelength is the distance between two consecutive crest .Wavelength of the red color is minimum and wavelength of the violet color is maximum in the light spectrum.
So the answer is B.
Electromagnetic spectrum
a the atom loses 1 proton to have a total of 34
Answer: 3.63 km/s
Explanation:
The escape velocity equation for a craft launched from the Earth surface is:
Where:
is the escape velocity
is the Universal Gravitational constant
is the mass of the Earth
is the Earth's radius
However, in this situation the craft would be launched at a height 
over the Eart's surface with a space elevator. Hence, we have to add this height to the equation:
Finally:
