Take east to be the positive direction. Then the resultant force from adding <em>F</em>₁ and <em>F</em>₂ is
<em>F</em>₁ + <em>F</em>₂ = (-45 N) + 63 N = 18 N
which is positive, so it's directed east.
To this we add a third force <em>F</em>₃ such that the resultant is 12 N pointing west, making it negative, so that
18 N + <em>F</em>₃ = -12 N
<em>F</em>₃ = -30 N
So <em>F</em>₃ has a magnitude of 30 N and points west.
The answer is definitely C.) their molecules move at the same average speed
Complete Question
The complete question is shown on the first uploaded image
Answer:
The wavelength is
Explanation:
From the question we are told that
The distance of the slit to the screen is 
The order of the fringe is m = 6
The distance between the slit is
The fringe distance is 
Generally the for a dark fringe the fringe distance is mathematically represented as
![Y = \frac{[2m - 1 ] * \lambda * D }{2d}](https://tex.z-dn.net/?f=Y%20%20%3D%20%5Cfrac%7B%5B2m%20%20-%201%20%5D%20%2A%20%20%5Clambda%20%2A%20%20D%20%20%7D%7B2d%7D)
=> ![\lambda = \frac{Y * 2 * d }{[2*m - 1] * D}](https://tex.z-dn.net/?f=%5Clambda%20%20%3D%20%20%5Cfrac%7BY%20%2A%20%202%20%2A%20%20d%20%7D%7B%5B2%2Am%20%20-%20%201%5D%20%2A%20%20D%7D)
substituting values
=> ![\lambda = \frac{0.019 * 2 * 0.9*10^{-3} }{[2*6 - 1] * 5}](https://tex.z-dn.net/?f=%5Clambda%20%20%3D%20%20%5Cfrac%7B0.019%20%2A%20%202%20%2A%20%200.9%2A10%5E%7B-3%7D%20%7D%7B%5B2%2A6%20%20-%20%201%5D%20%2A%20%205%7D)
=> 

Answer:
The distance that you marginally able to discern that there are two headlights rather than a single light source is 6.084 km
Explanation:
Given:
d = distance = 0.679 m
λ = wavelength of the light = 537 nm = 537x10⁻⁹m
dp = pupil diameter = 4.81 mm = 0.00481 m
Question: What distance, in kilometers, are you marginally able to discern that there are two headlights rather than a single light source, dx = ?
For the separation of the peak from the central maximum it is:

In this case, the two small sources of the headlights have the same angle as the images that form inside the eye
