Answer:
Explanation:
Given
Frictional Force is balanced by force due to car acceleration
Frictional force
The thermal efficiency of an engine is
where
W is the work done by the engine
Q is the heat absorbed by the engine to do the work
In this problem, the work done by the engine is W=200 J, while the heat exhausted is Q=600 J, so the efficiency of the machine is
Mainly because of the higher energy of blue light than red light.
In fact, light is made of photons, each one carrying an energy equal to
where h is the Planck constant while f is the frequency of the light.
The frequency of red light is approximately 450 THz, while the frequency of blue light is about 650 Hz. Higher frequency means higher energy, so blue light is more energetic than red light and therefore it can cause more damages than red light.
He needs to improve his endurance time.