Answer:
Frequency, 
Explanation:
Given that,
Wavelength of the light,

We need to find the frequency of light. We know that light is an electromagnetic wave. It moves with the speed of light. So,

f is the frequency of light

So, the frequency of light is
. Hence, this is the required solution.
Answer:
11.8 m/s
Explanation:
At the top of the hill, there are two forces on the car: weight force pulling down (towards the center of the circle), and normal force pushing up (away from the center of the circle).
Sum of forces in the centripetal direction:
∑F = ma
mg − N = m v²/r
At the maximum speed, the normal force is 0.
mg = m v²/r
g = v²/r
v = √(gr)
v = √(9.8 m/s² × 14.2 m)
v = 11.8 m/s