A man walks along a straight path at a speed of 4 ft/s. A searchlight is located on the ground 20 ft from the path and is kept focused on the man. At what rate is the searchlight rotating when the man is 15 ft from the point on the path closest to the searchlight

Answers

Answer 1

Answer:

0.128rad/sec

Step-by-step explanation:

Let x represent the between the man and the point on the path

θ = the angle

dx/dt = 4 ft/s

dθ/dt = rate is the searchlight rotating when the man is 15 ft from the point on the path closest to the searchlight

tan θ = x/20 ft

Cross Multiply

20tan θ = x

dx/dt = 20sec² θ dθ/dt

dθ/dt = 1/20 × cos² θ dx/dt

dθ/dt= 1/20 × cos² θ × 4

dθ/dt = 1/5 × cos² θ

Note : cos θ = 4/5

dθ/dt = 1/5 × (4/5)²

dθ/dt = 16/125

dθ/dt = 0.128rad/sec


Related Questions

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solve this equation
a^n+b^n=

Answers

Hey can someone help me with my latest question no one‘s helping me and I really need it

Ellie bakes 12 muffins everyday since Monday. Jacob said that on Friday, she would be able to bake 72 muffins in total. Is Jacob right? Yes or no, explain. :)

Answers

No

Explanation:

If Ellie started on Monday and made 12 muffins each day until Friday she would have made 60 muffins

12x5 = 60

Find the slope of the line

Answers

(0,5) is the answer

The perimeter of a rectangular outdoor patio is 66 ft. The length is 3 ft greater than the width. What are the dimensions of the patio?

Answers

Answer:

width = 15 ft

length = 18 ft

Step-by-step explanation:

lets assume the width is w, and length is l.

For the first equation, we all know that a rectangle is 2 widths and 2 lengths added up, which in "math" language looks like this:

2w+2l= 66

for the second equation, the problem says that the length is 3 ft greater than the width. From there, we can derive the equation:

w+3 = l

Now you can substitute one of the variables, length or width, but it is easier to do length. The equation ends up being:

2(w+3) + 2w = 66

Distributive property:

2w+6+2w = 66

which is equal to:

4w+6 = 66

which finally is:

w=15 ft.

Now that we know the width, we can just add 3 to the width to get the length, according to the problem. You get:

L = 18 ft.

the half life of c14 is 5730 years. Suppose that wood found at an archeological excavation site contains about 35% as much C14 as does living plant material. Determine when the wood was cut

Answers

Answer:

The wood was cut approximately 8679 years ago.

Step-by-step explanation:

At first we assume that examination occured in 2020. The decay of radioactive isotopes are represented by the following ordinary differential equation:

[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dm}{dt}[/tex] - First derivative of mass in time, measured in miligrams per year.

[tex]\tau[/tex] - Time constant, measured in years.

[tex]m[/tex] - Mass of the radioactive isotope, measured in miligrams.

Now we obtain the solution of this differential equation:

[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]

[tex]\ln m = -\frac{1}{\tau} + C[/tex]

[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Where:

[tex]m_{o}[/tex] - Initial mass of isotope, measured in miligrams.

[tex]t[/tex] - Time, measured in years.

And time is cleared within the equation:

[tex]t = -\tau \cdot \ln \left[\frac{m(t)}{m_{o}} \right][/tex]

Then, time constant can be found as a function of half-life:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)

If we know that [tex]t_{1/2} = 5730\,yr[/tex] and [tex]\frac{m(t)}{m_{o}} = 0.35[/tex], then:

[tex]\tau = \frac{5730\,yr}{\ln 2}[/tex]

[tex]\tau \approx 8266.643\,yr[/tex]

[tex]t = -(8266.643\,yr)\cdot \ln 0.35[/tex]

[tex]t \approx 8678.505\,yr[/tex]

The wood was cut approximately 8679 years ago.

Which expression is the coefficient of the n term -1

Answers

Answer:

C. -2n² - n + 5

Step-by-step explanation:

In expression C, the coefficient of the n term is -1;

  The expression in choice C is given as:

               -2n² - n + 5

The coefficient is the number before a variable;

  For n², the coefficient is -2

    for n, the coefficient is -1

18 feet above ground level and 7 feet below ground level

Answers

Answer:

11

Step-by-step explanation:

State the domain of the following mapping

Answers

Answer:

where's the map

Step-by-step explanation:

70 + x + 55 + 30 = 180

Answers

Answer:

x=25

Step-by-step explanation:

First, we add all like terms. Then, we solve for x.

[tex]70+x + 55 + 30 = 180\\x+70 + 55 + 30 = 180\\x+155=180\\x=25[/tex]

We can rearrange some things because order does not matter with addition. Next, we just use basic equation solving techniques.

Answer:

25. Hope this helps :)

Step-by-step explanation:

180-70=110

110-55=55

55-30=25

Your missing answer would be 25

X=25

anyone in flvs? we should find each other in live lessons lol

Answers

Answer:

nope

Step-by-step explanation:

Calculate.
(2x105)(4.3x109)
Write your answer in scientific notation.

Answers

Answer:

9.8427x10⁴

Step-by-step explanation:

Answer:

98427x^2

9.8427x10^4

Step-by-step explanation:

Number 10 plzz???????

Answers

%error=(6.5g/mol - 7g/mol)/(7g/mol) * 100= 7.14% error

Help me with this question quick PLZz

Answers

Answer:7 to 3

Step-by-step explanation:

Answer:

3:10

Step-by-step explanation:

3 Parrots

Total Number of Birds: 3+7=10

Everglades National Park is 225 mi long. What scale is needed to draw a map of Everglades National Park that is 10 in. long?


A. 1 in. = 22.5 mi

B. 10 in. = 225 mi

C. 1 in. = 0.04 mi

D. 10 in. = 22.5 mi

Answers

Answer:

A. 1 in. = 22.5 mi

Step-by-step explanation:

Since 22.5 x 10 = 225, we can conclude that this will fit the scale needed. B. is incorrect because it is simply illogical in context with a scale and the question. C. is incorrect since 10 x 0.04 is 0.4, which does not equal 10. D. is incorrect since we need the scale to add up to equal 225 mi, not 22.5.

Hope this helps!

ok so if someone needs 2 1/4 cups of water for 1 cup of rice then if they use 1/3 cup of rice how much water would they need

Answers

You would need 3/4 cups of water.

7th grade math help me plzzzz

Answers

Answer:

a. -14

b. -13

c. -5

d. -3

e. -12

f. 0

Step-by-step explanation:

hope it helps

Answer:

A is -14.

B is -13

C is -5

D is -3

E is -12

F is 0

Step-by-step explanation:

A, B, E both numbers are negative so you just add them together and add a negative sign.

C would read 4-9

D 10-7 and add a - to the answer

F is 6-6

rewrite the equation 10=1,000 with an exponet that makes it true .​

Answers

10^3= 1,000
hope this helps :)

Answer:

[tex]10^3=1,000[/tex]

Step-by-step explanation:

The expression 10=1,000 is obviously false, but we can make it true by rewriting it with an exponent.

Note that 1,000=10*10*10

Or, equivalently:

[tex]1,000=10^3[/tex]

Thus, if we modify the original false expression and add an exponent 3 to the base 10, then it would be true:

Original:

10=1,000 => false

Rewritten true:

[tex]\boxed{10^3=1,000}[/tex]

What is the measure of an exterior angle of a regular 14-sided polygon? Enter your answer as a decimal in the box. Round to the nearest tenth of a degree.

Answers

Answer:

21.715 degrees.

Step-by-step explanation:

There are 14 vertexes (vertices) for a 14-gon. It is 'regular' so all these angles are equal. So the exterior angle of each is 180-154.285 = 21.715 degrees.

I need help nowwwwww !!!!!????

Answers

you should just have to times the yards by three like the second one is 12

Whats 27.16 - 3.1 x 1.4 evaluated?
PLEASE HELP

Answers

Answer:

22.82

Step-by-step explanation:

can u plz mark me as brainliest??

Answer:

22.82

Step-by-step explanation:

3.1*1.4 = 4.34

27.16-4.34 = 22.82

[edited, I messed up the order of operations before, sorry]

In an attempt to improve brand recognition, the marketing department of AC Sports is
creating conical paper water cups with their brand printed around the surface of the
cup. The cups will be sent to athletic departments for free. About how much space do
the graphic artists working on the design have to work with if the cup will have a
diameter of 2.5 inches and a height of 3.5 inches?

Answers

Answer:

about 37.31 inches of space

Step-by-step explanation:

In this case, you would need to find the area of a cylinder with these dimensions.

Formula: 2πrh+2πr²

The r is the radius, and since the diameter in this situation would be 2.5, the radius would be 1.25.

2π(1.25)(3.5)+2π(1.25)²

2π4.375+2π1.5625

8.75π+3.125π

37.3064128

about 37.31 inches of space

Two people start walking at the same time in the same direction. One person walks at 8 mph and the other

person walks at 3 mph. In how many hours will they be 1.25 miles apart?

Answers

Answer:

0.25hours  

Step-by-step explanation:

Data

speed v1=8mph

speed v2=3mph

distance= 1.25

time t=?

speed= distance/time

distance=speed*time

1.25=8*t-3*t

1.25=8t-3t

1.25=5t

t=1.25/5

t=0.25hours

In minutes it is 15min

-4 (2x + 13) + 3x = 80
How do you solve this out and get the answer

Answers

Answer:

-132/5

Step-by-step explanation:

-4(2x+13) + 3x = 80

-8x - 52 + 3x = 80

-5x = 80+52

5x = -132

x = -132/5

Feel free to mark this as brainliest! :D

In a certain state's lottery, 45 balls numbered 1 through 45 are placed in a machine and eight of them are drawn at random. If the eight numbers drawn match the numbers that a player had chosen, the player wins $1,000,000. In this lottery, the order in which the numbers are drawn does not matter.

Compute the probability that you win the million-dollar prize if you purchase a single lottery ticket. Write your answer as a reduced fraction.
P
(win) =

A single lottery ticket costs $2. Compute the Expected Value, to the state, if 10,000 lottery tickets are sold. Round your answer to the nearest dollar.
Answer: $
A single lottery ticket costs $2. Compute the Expected Value, to you, if you purchase 10,000 lottery tickets. Round your answer to the nearest dollar.
Answer: $

Answers

Step-by-step explanation:

The order of the numbers doesn't matter, so we'll use combinations instead of permutations.  The number of combinations is:

₄₅C₈ = 215,553,195

So the probability of a ticket having the winning combination is 1 / 215,553,195.

The expected value to the state is:

E(X) = 10,000 (1) ($2) + 10,000 (1 / 215,553,195) (-$1,000,000)

E(X) = $19954

The expected value to you is:

E(X) = 10,000 (1) (-$2) + 10,000 (1 / 215,553,195) ($1,000,000)

E(X) = -$19954

2
Divide: 4:- =
5
HELP FAST!!!!!!!!!

Answers

10/4  if its right also have a good my dude

Dale has three dollars more than twice the amount of money that Leo has.

Which statement makes this comparison using the correct variable expression?

A. If Leo has d dollars then Dale has 2(3) + D dollars.
B. If Leo has d dollars then Dale has 2d + 3 dollars.
C. If Leo has d dollars then Dale has d +2+3 dollars.
D. If Leo has d dollars then Dale has d/2 + 3 dollars.

Please help y'all I don't get this can you guys explain to?

Answers

Answer:

is leo has d dollars then dale has 2d + 3 dollars

Step-by-step explanation:

dale has twice the amount and three extra dollars.

so 2 x d is 2d

2d + 3

Which ordered pair, if included in this relation, would cause it to no
longer be a function?

Answers

Answer:

(-6,3)

Step-by-step explanation:

Simplify (-4/5)divided by (3/-2). -8/15 -6/5 6/5 8/15

Answers

Answer:

8/15

Step-by-step explanation:

-4/5 ÷ -3/2

Copy dot flip

-4/5 * -2/3

Multiply the numerators

8

Multiply the denominators

15

Put the numerator over the denominator

8/15

Answer: 8/15

Step-by-step explanation: (-4/5)divided by (3/-2) is 8/15.

X+ 2 = 5 and y-3 = 2

Answers

Answer:

x=3

y=5

because 5-2=3 so 3 is x

and 2+3 is 5 so y is 5

Answer:

X = 3, Y =

Step-by-step explanation:

This is because 2+3=5,

and5-3=2

Write an equation in the line in slope intercept form

Answers

Answer:

Y=2x-1

Step-by-step explanation:

In order to find the slope, its rise over run. So you would move from (0,-1) to the next point it intercepts, (1,1) and find it from there

As for the Y-Intercept, it would just be wherever the line connects with the Y axis, which happens to be (0,-1) or Negative 1.

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