The Doppler effect occurs when a source of sound or light
moves either toward or away from the observer.
Answer:
Violet Light
Explanation:
On one end of the spectrum is red light, with the longest wavelength. Blue or violet light has the shortest wavelength. White light is a combination of all colors in the color spectrum. It has all the colors of the rainbow.
Answer:
Impulse will be 12 kgm/sec
So option (b) will be correct option
Explanation:
We have given mass of the baseball m = 0.15 kg
Ball speed before hit 
Ball speed after hitting
( negative direction due to opposite direction )
We have to find the impulse
We know that impulse is equal; to the change in momentum
So change in momentum = 
So option (b) will be correct option
U = 6.5 m/s, initial speed
t = 3.6 s, time
a = 0.92 m/s², acceleration
Let v = the final velocity.
Then
v = u +at
v = (6.5 m/s) + (0.92 m/s²)*(3.6 s) = 9.812 m/s
Answer: 9.81 m/s