PLEASE ANSWER FAST!!!!

Does this EVER end? All help appreciated

sergeinik [125]

Answer:

Step-by-step explanation:

According to Pythagoras Theorem a² + b² = c²

And the questio is having a right triangle in it so,

(Height of the building)² + (Length of the shadow)² = (The distance from the top of the building to the tip of the shadow)²

⇒ a² + (12)² = (20)²

⇒ a² = (20)² - (12)²

⇒ a² = 400 - 144

⇒ a² = 256

⇒ a = √256

⇒ a = 16

6 0

3 years ago

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In order to safely land, the angle that a plane approaches the runway should be no more than 15°. A plane is approaching Ottawa

belka [17]

9514 1404 393

Answer:

9.5°, yes

Step-by-step explanation:

The relevant trig relation is ...

Tan = Opposite/Adjacent

The distance opposite the angle of elevation is the plane's height, 500 m. The distance adjacent to the angle of elevation is the horizontal distance to the plane, 3 km = 3000 m. Then the angle is found from ...

tan(α) = 500/3000 = 1/6

α = arctan(1/6) ≈ 9.46°

The plane is approaching at an angle of 9.46°. It is safe to land, since that angle is less than 15°.

_____

Additional comment

The usual descent angle for most commercial air traffic is 3°. Some airport geography demands it be different (steeper). A higher descent angle can put undue stress on the landing gear.

5 0

3 years ago

A sled is being held at rest on a slope that makes an angle theta with the horizontal. After the sled is released, it slides a d

Alenkasestr [34]

Answer:

μ = Sin θ * d₁ / (d₂ - Cos θ*d₁)

d₂ = (d₁*Sin θ) / μ

Step-by-step explanation:

a) We apply The work-energy theorem

W = ΔE

W = - Ff*d

Ff = μ*N = μ*m*g

Distance 1:

- Ff*d₁ = Ef - Ei

⇒ - (μ*m*g*Cos θ)*d₁ = (Kf+Uf) - (Ki+Ui) = (Kf+0) - (0+Ui) = Kf - Ui

Kf = 0.5*m*vf² = 0.5*m*v²

Ui = m*g*h = m*g*d₁*Sin θ

then

- (μ*m*g*Cos θ)*d₁ = 0.5*m*v² - m*g*d₁*Sin θ

⇒ - μ*g*Cos θ*d₁ = 0.5*v² - g*d₁*Sin θ (I)

Distance 2:

- Ff*d₂ = Ef - Ei

⇒ - (μ*m*g)*d₂ = (0+0) - (Ki+0) = - Ki

Ki = 0.5*m*vi² = 0.5*m*v²

then

- (μ*m*g)*d₂ = - 0.5*m*v²

⇒ μ*g*d₂ = 0.5*v² (II)

If we apply (I) + (II)

- μ*g*Cos θ*d₁ = 0.5*v² - g*d₁*Sin θ

μ*g*d₂ = 0.5*v²

⇒ μ*g (d₂ - Cos θ*d₁) = v² - g*d₁*Sin θ (III)

Applying the equation (for the distance 1) we get v:

vf² = vi² + 2*a*d = 0² + 2*(g*Sin θ)*d₁ ⇒ vf² = 2*g*Sin θ*d₁ = v²

then (from the equation III) we get

μ*g (d₂ - Cos θ*d₁) = 2*g*Sin θ*d₁ - g*d₁*Sin θ

⇒ μ (d₂ - Cos θ*d₁) = Sin θ * d₁

⇒ μ = Sin θ * d₁ / (d₂ - Cos θ*d₁)

b)

If μ is a known value

d₂ = ?

We apply The work-energy theorem again

W = ΔK ⇒ - Ff*d₂ = Kf - Ki

Ff = μ*m*g

Kf = 0

Ki = 0.5*m*v² = 0.5*m*2*g*Sin θ*d₁ = m*g*Sin θ*d₁

Finally

- μ*m*g*d₂ = 0 - m*g*Sin θ*d₁ ⇒ d₂ = Sin θ*d₁ / μ

3 0

3 years ago

There are a total of 114 oak and pine trees on a piece of land. There are 26 fewer oak trees than pine trees. There is a regulat

umka21 [38]

Answer:

c

Step-by-step explanation:

3 0

3 years ago

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What is this trinomial in factored form? 3a^2-2a-1

Dafna1 [17]

Simplifying 3a2 + -2a + -1 = 0 Reorder the terms: -1 + -2a + 3a2 = 0 Solving -1 + -2a + 3a2 = 0 Solving for variable 'a'. Factor a trinomial. (-1 + -3a)(1 + -1a) = 0 Subproblem 1Set the factor '(-1 + -3a)' equal to zero and attempt to solve: Simplifying -1 + -3a = 0 Solving -1 + -3a = 0 Move all terms containing a to the left, all other terms to the right. Add '1' to each side of the equation. -1 + 1 + -3a = 0 + 1 Combine like terms: -1 + 1 = 0 0 + -3a = 0 + 1 -3a = 0 + 1 Combine like terms: 0 + 1 = 1 -3a = 1 Divide each side by '-3'. a = -0.3333333333 Simplifying a = -0.3333333333 Subproblem 2Set the factor '(1 + -1a)' equal to zero and attempt to solve: Simplifying 1 + -1a = 0 Solving 1 + -1a = 0 Move all terms containing a to the left, all other terms to the right. Add '-1' to each side of the equation. 1 + -1 + -1a = 0 + -1 Combine like terms: 1 + -1 = 0 0 + -1a = 0 + -1 -1a = 0 + -1 Combine like terms: 0 + -1 = -1 -1a = -1 Divide each side by '-1'. a = 1 Simplifying a = 1Solutiona = {-0.3333333333, 1}

4 0

3 years ago