B is the correct option.
1. Given eqn;
S(t) = 1/2t² - 4t + 8
2.Differentiate the above eqn with respect to t;
<u>d(S(t))</u> = t - 4
dt
When distance, S, is differentiated it results to velocity.
V = t - 4
at t = 10
V = 10 - 4
V = 6 feet/s
Answer:

Explanation:
We need to find the energy for an electron to jump from n = 1 to n = 4.
The energy in transition from 1 state to another is given by :

The difference in energy for n = 1 to n = 4 is:

So, the required energy is equal to
.
south = -(north)
Displacement = (4 km north) + (2 km south) + (5 km north) + (5 km south)
Displacement = (4 km north) - (2 km north) + (5 km north) - (5 km north)
Displacement = (4 - 2 + 5 - 5) km north
<u>Displacement = 2 km north </u>