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gizmo_the_mogwai [7]
3 years ago
11

4 This question has several parts that must be completed sequentially. If you skip a part of the question, you will not receive

any points for the skipped part, and you will not be able to come back to the skipped part. Tutorial ExerciseA boat leaves a dock at 8:00 PM and travels due south at a speed of 20 km/h. Another boat has been heading due east at 15 km/h and reaches the same dock at 9:00 PM How many minutes after 8:00 PM were the two boats closest together
Physics
1 answer:
zubka84 [21]3 years ago
3 0

Answer:at 21.6 min they were separated by 12 km

Explanation:

We can consider the next diagram

B2------15km/h------->Dock

|

|

B1 at 20km/h

|

|

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.

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A ladder rests against a vertical wall at a point 12 feet from the floor. The angle formed by the ladder and the floor is 63°. C
GenaCL600 [577]

Answer:

length of the ladder is 13.47 feet

base of wall to latter distance 6.10 feet

angle between ladder and the wall is 26.95°

Explanation:

given data

height h  = 12 feet

angle 63°

to find out

length of the ladder ( L) and length of wall to ladder ( A) and angle between  ladder and the wall

solution

we consider here angle between base of wall and floor is right angle

we apply here trigonometry rule that is

sin63 = h/L

put here value

L = 12 / sin63

L = 13.47

so length of the ladder is 13.47 feet

and

we can say

tan 63 = h / A

put here value

A = 12 / tan63

A = 6.10

so base of wall to latter distance 6.10 feet

and

we say here

tanθ = 6.10 / 12

θ = 26.95°

so angle between ladder and the wall is 26.95°

8 0
3 years ago
A long, East-West-oriented power cable carrying an
Alla [95]

Answer:

200A

Explanation:

Given that

the distance between earth surface and power cable d = 8m

when the current is flowing through cable , the magnitude flux density at the surface is 15μT

when the current flow throught is zero the magnitude flux density at the surface is 20μT

The change in flux density due to the current flowing in the power cable is

B = 20μT - 15μT

B =5μT -----(1)

The expression of magnitude flux density produced by the current carrying cable is

B=\frac{\mu_0I}{2\pi d}-----(2)

Substitute the value of flux density

B from eqn 1 and eqn 2

\frac{\mu_0I}{2\pi d}=5\times 10^-^6\\\\\frac{(4\pi \times 10^-^7)I}{2 \pi (8)} =5\times 10^-^6\\\\I=200A

Therefore, the magnitude of current I is 200A

8 0
2 years ago
What is the momentum of a 1550kg car that is traveling 38.0 m/s?
konstantin123 [22]

Answer:

p = 58,900 kg m/s

Explanation:

p = m × v

p = 1,550 × 38.0

p = 58,900 kg m/s

5 0
2 years ago
PLSS HELP ITS TIMED <br> WILL MARK BRAINLIEST
dlinn [17]

Answer:

tjfd

Explanation:

tuff

4 0
3 years ago
13. in batesian mimicry, a palatable species gains protection by mimicking an unpalatable one. imagine that individuals of a pal
fiasKO [112]

Batesian mimicry is an adaptive feature associated with the coloration of a given species in a given environment.

<h3>What is Batesian mimicry?</h3>

Batesian mimicry can be defined as a type of adaptive feature associated with the coloration of a particular species and/or population.

On the first island, the color of the population won't change because of the absence of predators.

On the second island, the color of the population will change because of the presence of predators that can be alerted by the color.

On the third island, the color of the population won't change because of the presence of a species with a similar color.

In conclusion, Batesian mimicry is an adaptive feature associated with the coloration of a given species in a given environment.

Learn more about Batesian mimicry here:

brainly.com/question/14139071

#SPJ1

6 0
2 years ago
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