Answer:
Initial velocity describes how fast an object travels when gravity first applies force on the object. On the other hand, the final velocity is a vector quantity that measures the speed and direction of a moving body after it has reached its maximum acceleration.
Explanation:
Answer:
The farther star will appear 4 times fainter than the star that is near to the observer.
Explanation:
Since it is given that the luminosity of the 2 stars is same thus they radiate the same energy per unit time
Consider a spherical wave front of energy 'E' that leaves both the stars (Both radiate 'E' as they have same luminosity)
This Energy is spread over the whole surface area of sphere Thus when the wave front is at a distance 'r' the energy per unit surface area is given by

For the star that is twice away from the earth the distance is '2r' thus we will receive an energy given by
Hence we sense it as 4 times fainter than the nearer star.
Answer:

Explanation:
The principle of conservation of momentum, states that if the sum of the forces acting on a system is null, the initial total momentum of the system before a collision equals the final total momentum of the system after the collision. The collision is completely inelastic, which means that the players remain stick to each other after the collision:

Answer:
a

b

c
Explanation:
From the question we are told that
The angle of incidence is 
The refractive index of water is 
Generally Snell's law is mathematically represented as

Here
is the refractive index of air with value 
is the angle of refraction
So
![\theta _2 = sin^{-1}[\frac{n_1 * sin(\theta _1)}{n_2} ]](https://tex.z-dn.net/?f=%5Ctheta%20_2%20%20%3D%20%20sin%5E%7B-1%7D%5B%5Cfrac%7Bn_1%20%2A%20sin%28%5Ctheta%20_1%29%7D%7Bn_2%7D%20%5D)
=> ![\theta _2 = sin^{-1}[\frac{1.3 * sin(10)}{1} ]](https://tex.z-dn.net/?f=%5Ctheta%20_2%20%20%3D%20%20sin%5E%7B-1%7D%5B%5Cfrac%7B1.3%20%2A%20sin%2810%29%7D%7B1%7D%20%5D)
=> 
Given that the angle should not be greater than
then the angle of incidence will be
![\theta _1 = sin^{-1}[\frac{n_2 * sin(\theta _2)}{n_1} ]](https://tex.z-dn.net/?f=%5Ctheta%20_1%20%20%3D%20%20sin%5E%7B-1%7D%5B%5Cfrac%7Bn_2%20%2A%20sin%28%5Ctheta%20_2%29%7D%7Bn_1%7D%20%5D)
=> ![\theta _1 = sin^{-1}[\frac{1 * sin(45)}{1.3} ]](https://tex.z-dn.net/?f=%5Ctheta%20_1%20%20%3D%20%20sin%5E%7B-1%7D%5B%5Cfrac%7B1%20%2A%20sin%2845%29%7D%7B1.3%7D%20%5D)
=> 
Generally for critical angle is mathematically represented as
![\theta_c = sin^{-1}[\frac{n_2}{n_1} ]](https://tex.z-dn.net/?f=%5Ctheta_c%20%20%3D%20%20sin%5E%7B-1%7D%5B%5Cfrac%7Bn_2%7D%7Bn_1%7D%20%5D)
=>
=>