We can find the answer by solving the two equations simultaneously.

equation 1: y = -0.4x^2 +3xequation 2: x + y = 10
We need to write equation to with y as the subject:equation 2: y = 10 - x

equation 1 = equation 2:
10 - x = -0.4x^2 + 3x0.4x^2 - 4x + 10 = 02x^2 - 20 + 50 = 0(2x - 10)(x - 5) = 0x = -10/2 or x = 5

But x >= 0 (the question says it's a height above the water), so x = 5

Substituting x = 5 into one of the equations:
y = 10 - x
y = 10 - 5
y = 5

So the answer is C

7 0

3 years ago

100 points+Brainliest for correct answer

goblinko [34]

Answer:

The electron moved down to an energy level and has an energy of

$10.92 \times 10^{-19} \textsf{J}$

Step-by-step explanation:

$\textsf{initial energy level of electron}= 16.32 \times 10^{-19} \textsf{J}$

$\triangle E =\textsf{energy released}= 5.4 \times 10^{-19} \textsf{J}$

A positive energy change means that the electron absorbs energy, while a negative energy change implies a release of energy from the electron.

Therefore, when an electron absorbs energy, the electron moves up to higher energy levels, and when an electron releases energy, it moves to lower energy levels.

$\triangle E=E_2-E_1$