Estimate the sum of 279 and 217

The equation h=7sin(pi/21t)+28 can be used to model the height, h, in feet of the end of one blade of a windmill turning on an a

satela [25.4K]

Answer:

7 feet is the length of the blade of the windmill.

Step-by-step explanation:

We have the equation

h = 7 sin(pi/21t) + 28 ------ eq1

At time 't' = 0, the end of the blade is pointing to the right parallel to the ground meaning it is at the same height as the other end. (Ф = 0°)

So, by calculating the maximum height of this end at Ф = 90°. we can calculate the length of the blade.

Now, we know that a general model equation of a circular simple harmonic motion is represented as : y = A sinωt + k ----- eq2

Where A is the amplitude that is, maximum displacement from mean to maximum position.

ω is the angular frequency.

Comparing eq1 and eq2:

A = 7

so the difference in blades end height at Ф = 0° and Ф = 90° is 7 feet.

Hence, the length of the blade is 7 feet.

4 0

3 years ago

Read 2 more answers

A supply company manufactures copy machines. The unit cost C (the cost in dollars to make each copy machine) depends on the numb

Ugo [173]

To answer this item, we take the differential of the equation and equate to zero.

C(x) = 0.8x² - 256x + 25939

Differentiation,
dC(x) = 1.6x - 256
dC(x) = 1.6x - 256 = 0

The value of x from the derived equation above is 160.

Thus, the number of machine to be made in order to minimize the cost should be 160.

4 0

3 years ago

Read 2 more answers

11x^3 + 15x^2 - 25x + 7 = 0

IgorLugansk [536]

Answer:

x1 = −2.414

x2 = 0.414

x3 = 0.636

5 0

3 years ago

The width of DNA is approximately 0.0000000025 meter wide. In scientific notation, 6 times the width of DNA can be written as 1.

Reptile [31]

The value of x is 15.0

8 0

3 years ago

Vectors! Please help! This is the last question OF MY WHOLE SEMESTER! I've tried it so many times and can't get it right. :(

Feliz [49]

Pictures always help; see the one I've attached for reference.

Call the first vector (from HQ to the supply drop) u and the second vector (from supply drop to medics) v. We then want to find w, the vector from the medics to HQ, which corresponds to the vector -(u + v). (This is because u + v is the vector pointing from HQ to the medics; we're talking about the one in the opposite direction.)

Write the vectors in horizontal/vertical component form:

u = (125 km) (cos 235º x + sin 235º y) = (-71.70 x - 102.39 y) km

v = (75 km) (cos 110º x + sin 110º y) = (-25.65 x + 70.48 y) km

Why these angles?

"55 degrees south of west" is 235º; due west is 180º from the positive horizontal axis, and you add 55º to this
"20 degrees west of north" is 110º; due north is 90º, so add 20º to this

Add the vectors:

u + v = (-97.35 x - 31.92 y) km

Multiply by -1 to get the vector w:

w = -(u + v) = (97.35 x + 31.92 y) km

The distance covered by this vector is equal to its magnitude:

||w|| = √((97.35 km)^2 + (31.92 km)^2) = 102.45 km

The direction θ is given by

tanθ = (31.92 km)/(97.35 km) ==> θ = 18.15º

6 0

3 years ago