Answer:at 21.6 min they were separated by 12 km
Explanation:
We can consider the next diagram
B2------15km/h------->Dock
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B1 at 20km/h
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V
So by the time B1 leaves, being B2 traveling at constant 15km/h and getting to the dock one hour later means it was at 15km from the dock, the other boat, B1 is at a distance at a given time, considering constant speed of 20km/h*t going south, where t is in hours, meanwhile from the dock the B2 is at a distance of (15km-15km/h*t), t=0, when it is 8pm.
Then we have a right triangle and the distance from boat B1 to boat B2, can be measured as the square root of (15-15*t)^2 +(20*t)^2. We are looking for a minimum, then we have to find the derivative with respect to t. This is 5*(25*t-9)/(sqrt(25*t^2-18*t+9)), this derivative is zero at t=9/25=0,36 h = 21.6 min, now to be sure it is a minimum we apply the second derivative criteria that states that if the second derivative at the given critical point is positive it means here we have a minimum, and by calculating the second derivative we find it is 720/(25 t^2 - 18 t + 9)^(3/2) that is positive at t=9/25, then we have our answer. And besides replacing the value of t we get the distance is 12 km.
To declare an image is real you would call it “authentic”
The correct answer to this is (A. Units Only).
It shows that there is a velocity of 35, but the units are missing.
Answer:
1. It undergoes reflection. 2. It undergoes refraction. 3. It undergoes diffraction.
Explanation:
1. It undergoes reflection. This is because it bounces off surfaces when incident on them.
2. It undergoes refraction. This is because it changes direction when it passes from one medium to another
3. It undergoes diffraction. This is because it spreads out when it passes through doors and windows similar in dimension to the dimensions of its wavelength
Answer:
For left = 0 N/C
For right = 0 N/C
At middle = 
N/C
Explanation:
Given data :-
б =
C/ m²
Considering the two thin metal plates to be non conducting sheets of charges.
Electric field is given by
1) To the left of the plate
= 0 N/C.
2) To the right of them.
= 0 N/C.
3) Between them.
= 
= 
= N/C
