14 m/s or 50km/h. See the details in the attached picture.
Explanation:
We have,
Speed of plane a is 900 km/h
Plane b is moving at a rate of 
It is required to find which plane is faster. To find which plane is faster, we need to compare their speeds.
Speed of a plane a is 900 km/h and that of plane b is 50 km/h. So, we can say that plane a is moving faster.
Answer: Looked it up but
Explanation:
When the skater lands on the track, the vertical component of his kinetic energy is converted to thermal energy. You can do experiments where there is no loss to thermal energy (only PE and KE conversions) by turning friction off and by making sure the skater doesn't leave the track.
Answer: True.
Explanation:
A resistance force is also known as friction. And the efficiency of a machine is affected by friction.
A machine of lower efficiency has higher magnitude of friction than a machine of higher efficiency.
Therefore, To obtain the same resistance force, a greater force must be exerted in a machine of lower efficiency than in a machine of higher efficiency. This is true
Answer:

Explanation:
Wien's displacement law states that the radiation of the black body curve for different temperatures will give peak values at different wavelengths and this wavelength is related inversely to the temperature.
Formally the law of Wien displacement states that the black body's spectral radiation per unit of wavelength, will give peaks at the wavelength of
which is given by the mathematical expression.
Here, b is proportionality constant with value of
The wavelength of the peak of the Gaussian curve is inversely related to temperature in degree kelvin.