Color corresponds to the wavelength of light waves.
The shortest light waves are "violet", the longest light waves are "red".
Answer:
Part a)
When there is no friction then acceleration is

Part b)
if there is friction force along the inclined then acceleration is

Explanation:
Part a)
As we know that the skier is on inclined plane
So here if there is no friction then net force along the inclined plane is given as

now acceleration of the skier is given as




Part b)
if there is friction force along the inclined then net force along the inclined plane is given as

now acceleration of the skier is given as




Three times of it's length