We are asked to solve for the index of refraction and the formula is n = c/v where "n" represents the index of refraction, "c" represents the speed of light in the vacuum while "v" represents the speed of another medium.
In the problem, we have the given values below:
c = 3 x 10^8 m/s
v = 2 x 10^8 m/s
n =?
Solving for n, we have the solution below:
n = 3x10^8 / 2x10^8
n = 1.5
The answer is 1.5 for the index of refraction.
<span>No. Work is not done if you carry a book across the room
at a constant velocity?
The force applied is perpendicular to the direction of motion. (C)</span>
Answer:

Explanation:
Given that,
Initial speed of the cart, u = 0
Let F force is applied to the cart for time
after which the car has speed v. The force on an object is given by :
F = ma
m is the mass of the cart
We need to find the speed of second cart, if the same force is applied for the same time to a second cart with twice the mass. Force becomes,



So, the speed of second cart is half of the initial speed of first cart. So, the correct option is (b).
Answer:
0.229 seconds
Explanation:
Given:
y₀ = 80.6 m
v₀ = 0 m/s
a = -9.8 m/s²
We need to find the difference in times when y = 10.8 m and y = 2.10 m.
When y = 10.8 m:
y = y₀ + v₀ t + ½ at²
10.8 = 80.6 + (0) t + ½ (-9.8) t²
10.8 = 80.6 − 4.9 t²
4.9 t² = 69.8
t = 3.774
When y = 2.10 m:
y = y₀ + v₀ t + ½ at²
2.10 = 80.6 + (0) t + ½ (-9.8) t²
2.10 = 80.6 − 4.9 t²
4.9 t² = 78.5
t = 4.003
The difference is:
4.003 − 3.774 = 0.229
The man has 0.229 seconds to get out of the way.
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