Answer:

Explanation:
Let the speed of light in vacuum is c and the speed of light in medium is v. Let the angle of incidence is i.
By using the definition of refractive index
refractive index of the medium is given by
n = speed of light in vacuum / speed of light in medium
n = c / v ..... (1)
Use Snell's law
n = Sin i / Sin r
Where, r be the angle of refraction
From equation (1)
c / v = Sin i / Sin r
Sin r = v Sin i / c

Explanation:
Given that,
A person walks 9.0 km directly east and then turns left and heads directly north for 12.0 km.
We need to find his displacement from the starting position.
We know that,
Displacement = shortest path covered

For direction,

Hence, this is the required solution.
Answer:
11.7 m/s
Explanation:
To find its speed, we first find the acceleration of the center of mass of a rolling object is given by
a = gsinθ/(1 + I/MR²) where θ = angle of slope = 4, I = moment of inertia of basketball = 2/3MR²
a = 9.8 m/s²sin4(1 + 2/3MR²/MR²)
= 9.8 m/s²sin4(1 + 2/3)
= 9.8 m/s²sin4 × (5/3)
= 1.14 m/s²
To find its speed v after rolling for 60 m, we use
v² = u² + 2as where u = initial speed = 0 (since it starts from rest), s = 60 m
v = √(u² + 2as) = √(0² + 2 × 1.14 m/s × 60 m) = √136.8 = 11.7 m/s
Answer:
c
Explanation:
this is because you move ( kinetic energy) your hands and clap the other person's hand, you will definitely hear sound right.