Answer:
a) 
b) 
c) 
d) 
Explanation:
Given:
- distance down the field in the first interval,

- time duration of the first interval,

- distance down the field in the second interval,

- time duration of the second interval,

- distance down the field in the third interval,

- time duration of the third interval,

a)
velocity in the first interval:



b)
velocity in the second interval:



c)
velocity in the third interval:



d)
We know that the average velocity is given as the total displacement per unit time.



More force needs to be applied
Answer:
Astronomers use a method similar to the one you used with your homemade quadrant. Twice the distance to the Sun, divided by the distance to the star (which is unknown so far) is equal to the tangent of the parallax angle of the star.
By definition, the refractive index is
n = c/v
where c = 3 x 10⁸ m/s, the speed of light in vacuum
v = the speed of light in the medium (the liquid).
The frequency of the light source is
f = (3 x 10⁸ m/s)/(495 x 10⁻⁹ m) = 6.0606 x 10¹⁴ Hz
Because the wavelength in the liquid is 434 nm = 434 x 10⁻⁹ m,
v = (6.0606 x 10¹⁴ 1/s)*(434 x 10⁻⁹ m) = 2.6303 x 10⁸ m/s
The refractive index is (3 x 10⁸)/(2.6303 x 10⁸) = 1.1406
Answer: a. 1.14