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.
Musical notation is the term used to describe the common system of signs used to denote the relative duration of long and short sounds.
<h3>What is a musical notation?</h3>
Music notation, often known as musical notation, is any technique used to graphically express audibly perceived music performed with instruments or sung by a human voice using written, printed, or other symbol-based representations. This includes notation for periods of silence like rests.
Throughout history, many civilizations have used different types of notation, and the knowledge of early musical notation is generally sparse. Different musical genres and cultural groups employ various methods of music notation, even during the same time period, such as the 2010s. For instance, while sheet music with staves and note-heads is the most popular method for professional classical musicians, the Nashville Number System is the main method used by professional country music session musicians.
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The correct answers are <span>starting friction and </span>static friction
Friction slows down all forces, but starting friction slows down or stops completely the start of motion.
Answer:
Explanation:
The forces compare together as a result of the fact that the force exerted by that of the ball and the force exerted by that of the wall both have the same magnitude.
A. A healthy body composition will improve range of motion and prevent injuries. Staying in a healthy weight range (BMI) prevents overexerting joints. It also helps increase range of motion which in turn reduces injury.