For the amusement of the guests, some hotels have elevators on the outside of the building. One such hotel is 400 feet high. You are standing by a window 100 feet above the ground and 150 feet away from the hotel, and the elevator descends at a constant speed of 20 ft/sec, starting at time t = 0, where t is time in seconds. Let θ be the angle between the line of your horizon and your line of sight to the elevator. 4 (a) Find a formula for h(t), the elevator's height above the ground as it descends from the top of the hotel. h(t) = (b) Using your answer to part (a), express θ as a function of time t. θ(t) = Find the rate of change of θ with respect to t. dθ dt = (c) The rate of change of θ is a measure of how fast the elevator appears to you to be moving. At what time does the elevator appear to be moving fastest? time = seconds At what height does the elevator appear to be moving fastest?

Answers

Answer 1

9514 1404 393

Answer:

  a.  h(t) = -20t +400

  b.  θ(t) = arctan(2 -2/15t); dθ/dt = -30/(1125 -120t +4t^2)

  c.  15 seconds; 100 ft

Step-by-step explanation:

a. The initial height of the elevator is 400 ft. The rate of change of height is -20 ft/s, so the height equation can be ...

  h(t) = -20t +400

__

b. The tangent of the angle above the line of sight is "opposite"/"adjacent":

  tan(θ) = (h(t) -100)/(150) = -2/15t +2

  θ(t) = arctan(2 -2/15t) . . . . radians

The derivative of the angle function is ...

  dθ/dt = 1/(1+(2 -2/15t)^2)(-2/15)

  dθ/dt = -30/(1125 -120t +4t^2)

__

c. The value of dθ/dt will have a peak where the denominator has a minimum, at t = -(-120)/2(4)) = 15. (The quadratic vertex coordinate is t=-b/(2a).)

The elevator appears to be moving fastest at t=15 seconds.

The height at that time is ...

  h(15) = 400 -20(15) = 100

The elevator appears to be moving fastest when it is at eye level, 100 ft above the ground.


Related Questions

In circle D, which is tangent to the circle?

Line G H
Line segment A B
CD
EF

Answers

Answer:

line segment A B

Step-by-step explanation:

it's really a ray, not a line segment

In circle D, the AB line segment is tangent to the circle.

What are the properties of the circle?

The circumference, which is the distance around the object, the diameter, which is the length of a circle measured from one end to the other and passing through its center, and the radius, which is equal to half of the diameter, are the three key characteristics.

The general coordinate equation of a circle is:

(x-h)² + (y - k)² = r²

Where,

(h, k) is the center of a circle,

"r" is the radius of the circle.

Since A line that only has one point where it crosses a circle is said to be tangent to the circle. The point of contact is the location where the circle and the tangent meet.

Thus, in the given figure AB is the tangent line segment of the circle D.

From the properties of the circle, we can state that,

FE is Diameter,

The CD is representing the radius, and

GH is representing the Secant line of the circle D.

Therefore, In circle D, the AB line segment is tangent to the circle.

Learn more about Circle here:

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What is 100% of 63?
PLEASE ANSWER QUICKLY

Answers

Answer:

100 percent of 63 is 63

Step-by-step explanation:

Answer:

63

Step-by-step explanation:

100 x 63 /100 = 63

Solve 3h+g=5h-hg for h

Answers

Answer: [tex]h=\frac{-g}{g-2}[/tex]

Step-by-step explanation:

Let's solve for h.

[tex]3h+g=5h-hg[/tex]

Step 1: Add [tex]gh[/tex] to both sides.

[tex]g+3h+gh=-gh+5h+gh[/tex]

[tex]gh+g+3h=5h[/tex]

Step 2: Add [tex]-5h[/tex] to both sides.

[tex]gh+g+3h+-5h=5h+-5h[/tex]

[tex]gh+g-2h=0[/tex]

Step 3: Add [tex]-g[/tex] to both sides.

[tex]gh+g-2h+-g=0+-g[/tex]

[tex]gh-2h=-g[/tex]

Step 4: Factor out the variable [tex]h[/tex].

[tex]h(g-2)=-g[/tex]

Step 5: Divide both sides by [tex]g-2[/tex].

[tex]\frac{h(g-2)}{g-2} =\frac{-g}{g-2}[/tex]

[tex]h=\frac{-g}{g-2}[/tex]

Answer:

[tex]h=\frac{-g}{g-2}[/tex]

can someone please help me with this one question! ​

Answers

Answer:

RST≈TSR FOR YOU PLAESE RANK ME HELPING HAND

7÷5=2. Prove It




Based on Critical Thinking and Reasoning. Not normal mathematics.

Answers

the answer is 1.4 not 2

Show your work and write an expression using the following criteria:
1. A dividend greater than 1,000
2. The quotient is 58 with a remainder of 22

Answers

Answer:

This is correct explanation

Step-by-step explanation:

A dividend is a number we want to divide by another number. It's supposed to be greater than 1000.

Quotient - the integer result of division. Remainder - well, what remains.

9/4 = 2, with remainder 1.

You want to find a number greater than 1000, which, when divided by another number, results in 37, with a remainder of 4.

I would multiply 37 by an increasing number until we get a product greater than 1000. This number is the one you are dividing by. Now add 4 to the product, so that when the sum is divided by the number you found we'll get a remainder of 4.

what is the solution of the equation ? 3=2w

Answers

Answer:

w = 1.5

Step-by-step explanation:

Question:To find the solution that is 'w'

Equation:3 = 2w

Solution:

3 = 2w

=> 2w = 3

[tex] = > w = \frac{3}{2} [/tex]

=> w = 1.5 (Ans)

What is the probability of randomly selecting a month of the year and not getting a month that has fewer than 30 days

Answers

Answer

11 out of 12

11/12

Step-by-step explanation:

Question 3 What is the equation of the parabola that opens up, has a vertex V(5,0), and a y-intercept of 50?​

Answers

Answer:

y=2(x-5)^2

Step-by-step explanation:

Vertex form:

y=a(x-p)^2+q

(p,q) = (5,0)

y=a(x-5)^2

y-intercept has coordinates (0,50) so, substitute x=0 and y= 50 in the above equation to find "a"

50=a(0-5)^2

50=25a

a=2

equation

y=2(x-5)^2

Original price of an SUV $12,000.00 Tax:5.3%

Answers

The tax would be $636 and the total cost would be $12,636 if that's what you're asking.

Point J(-3, -7) was rotated to J'(7, -3). How
many degrees was the rotation?

Answers

Answer:

90 clockwise

Step-by-step explanation:

Answer:

270 degrees

Step-by-step explanation:

If both numbers are negative it means its in the lower left quadrant, so to reach 7 and -3, that means we need to reach the lower right quadrant so a 270 degree turn works

What is the value of y in y = 2x - 5, when x = 3.9?

Answers

Answer:

Y = -3 and with x as 3.9 y equals 2.8

Step-by-step explanation:

(2,-6); m= -1/4
(Write an equation in point-slope form of the line that passes through the given point and has the given slope)

Answers

Answer:

y + 6 = -1/4(x - 2)

Step-by-step explanation:

Point slope form:  [tex]y - y_{1} = m(x - x_{1} )[/tex]

[tex]y - y_{1} = m(x - x_{1} )[/tex]    Substitute slope = -1/4 and point (2, -6)

[tex]y - (-6) =\frac{-1}4} (x - 2)\\[/tex]

y + 6 = -1/4(x - 2)

 

Show your work and write an expression using the following criteria:
1. A dividend greater than 1,000
2. The quotient is 58 with a remainder of 22

Answers

Answer:

this is correct

Step-by-step explanation:

A dividend is a number we want to divide by another number. It's supposed to be greater than 1000.

Quotient - the integer result of division. Remainder - well, what remains.

9/4 = 2, with remainder 1.

You want to find a number greater than 1000, which, when divided by another number, results in 37, with a remainder of 4.

I would multiply 37 by an increasing number until we get a product greater than 1000. This number is the one you are dividing by. Now add 4 to the product, so that when the sum is divided by the number you found we'll get a remainder of 4.

There are 63 students in band. This represents 30% of the grade. How many students are in the entire grade

Answers

So, the question is 63 is 30% of what number?

That can translate to the equation

     63 = 30% · x     or     63 = 0.3x

Divide by 0.3 and you get x = 210.

There are 210 students in band.

Answer:

210 students

Step-by-step explanation:

210 x (3/10) = 63

Hey dude! you want some make of noise? I'm Dj from Pennsylvania ​

Answers

……,,,,,,,,,,,,,,,,……..

Please take a look at the picture.

Answers

Answer:

A and B

Step-by-step explanation:

a) -x+0+(-x)=0

Combine like terms.

-2x+0=0

Subtract 0 from both sides.

-2x=0

Divide both sides by -2.

x=0

b) -x-(-x)=0

Remove parentheses.

-x+x=0

Combine like terms.

0=0

Hope this helps :)

27 red bikes out of 33 bikes

Answers

The total is 33 bikes. 27 out of the 33 bikes are red. Therefore, we have a number of parts to a whole, so we can create a fraction to calculate the percentage of red bikes.

27/33 = .818

.818 x 100 = 81.81%.

• To calculate a percentage, divide the numerator by the denominator and multiply by 100. Here’s a formula to remember: n/d•100, where n=numerator and d=denominator.

Therefore, 81.81% of the bikes are red.

Feel free to give Brainliest!

a number divided by 5 increased by 4

Answers

Answer:

(n/5)+4

Step-by-step explanation:

I think you were asking for the equation?

Answer:

X/5 + 4

Step-by-step explanation:

X is the “number”

The new Apple Watch series 7 cost $799. There is an additional 7% sales tax rate . If Oscar has a total of 850.00 to spend, will he be able to purchase the new Apple Watch Series 7? Explain.

Answers

The total available cash with Oscar will not be able to purchase the new Apple Watch Series 7 because the total cost of the watch is greater than available cash.

The given parameters;

cost of new Apple Watch Series 7, = $799sales tax, = 7%Oscars available cash = $850

The total cost of the new Apple Watch Series 7 is calculated as follows;

Total cost = 0.07(799)  +  799

Total cost = $854.93

Thus, we can conclude that the total available cash with Oscar will not be able to purchase the new Apple Watch Series 7 because the total cost of the watch is greater than available cash.

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I need help , how do we know if the graph are positive or negative

Answers

Answer:

The negatives are at the bottom and the positives are at the top, if you need help with the (x,y) let me know!!!

Step-by-step explanation:

Answer:

right and above side of graph are positive

and

left and bottom side of graph are negative

The angle of elevation of the top of a cliff from the point Q on the ground is 30°. On moving a distance of 20
m towards the foot of the cliff the angle of elevation increases to xº. If the height of the cliff is 17.3 m, then
find xo

Answers

On moving a distance of 20m towards the foot of the cliff the angle of

elevation increases to 60° .

The situation forms 2 right angle triangle.

The height of the cliff is the opposite side of the 2 triangles formed.

Using trigonometric ratio, the bigger triangle  can be represented as

follows:

tan 30 = opposite / adjacent

Let the distance from point Q to the foot of the cliff be d.

Therefore,

tan 30° = 17.3 / d

d = 17.3 / tan 30

d = 17.3 / 0.57735026919

d = 29.9644789709

d ≈ 30 m

Let's find the new angle when he moves 20 m towards the foot of the cliff.

The smaller triangle formed is used to find the new angle.

Therefore,

The new distance  from the foot of the cliff (adjacent side) = 30 - 20  = 10 m

tan x° = 17.3 / 10

tan x° = 1.73

x = tan ⁻¹ 1.73

x = 59.9705982385

x  ≈ 60°

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Given right triangle ABC, where side "c" is the
hypotenuse, angle B measures 44 degrees, and side
c measures 17 m, find the length of side b.
Round your answer to the nearest hundredth of
meter

Answers

Answer:

b = 11.81 m

Step-by-step explanation:

b = c . sinB = 17sin44 = 11.81

9.3 of sugar is need for every cake made how much sugar is needed for 6 cakes

Answers

Answer:

484836281726261919292762

Answer:

55.8

Step-by-step explanation:

if 1 cake needs 9.3, 6 cakes would need (6*9.3)

9.3 * 6 = 55.8

HELP ME OUT PLEASE!

How many total atoms of Nitrogen are shown in the formula below?

O 2

O 4

O 6

O 8​

Answers

Answer:

A) 2

Step-by-step explanation:

It shows it in the formula.

The values of x and y which satisfy the equations
x + 2 y = 27 and 2x - y = 19 are respectively
(A) 15 and 10
(B) 10 and 15
(C) 7 and 13
(D) 13 and 7

Answers

D) 13 and 7

This is because when the value of x is 13 and the value of y is 7, these equations both become true.

What sentence represents this equation? 912=15−x 912 ​is the same as a number decreased by 15. 15 decreased by 912 is the same as a number. A number is the same as the difference of 15 and 912. 912 is the same as 15 decreased by a number.

Answers

9 1/2 is the same as a number decreased by 15

I guess that's the right answer maybe i'm wrong if I am oh well

Find the line integral along the curve C from the origin along the x-axis to the point (6, 0) and then counterclockwise around the circumference of the circle x2 y2

Answers

Parameterize C by the two vector functions,

r(t) = (1 - t) (0, 0) + t (6, 0) = (6t, 0)

with 0 ≤ t ≤ 1, and

s(t) = (6 cos(t), 6 sin(t))

with 0 ≤ t ≤ π/2.

Then the line integral over C is equal to the sum of the line integrals over each path:

[tex]\displaystyle \int_C dS = \int_0^1 \|r'(t)\| \, dt + \int_0^{\frac{\pi}2} \|s'(t)\| \, dt[/tex]

[tex]\displaystyle \int_C dS = \int_0^1 \sqrt{6^2 + 0^2} \, dt + \int_0^{\frac{\pi}2} \sqrt{(-6\sin(t))^2 + (6\cos(t))^2} \, dt[/tex]

[tex]\displaystyle \int_C dS = 6 \int_0^1 dt + 6 \int_0^{\frac{\pi}2} dt[/tex]

[tex]\displaystyle \int_C dS = 6 + \frac{6\pi}2 = \boxed{6+3\pi}[/tex]

Can someone help me on this

Answers

Answer:

39V3 Sq.units of that will help you

what i ls the value of
[tex]\pi[/tex]

Answers

Step-by-step explanation:

π can be taken as approximation of 22/7 ≈ 3.14

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