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Marizza181 [45]
3 years ago
5

A street light is mounted at the top of a 15-ft-tall pole. A man 6 ft tall walks away from the pole with a speed of 4 ft/s along

a straight path. How fast is the tip of his shadow moving when he is 35 ft from the pole?
Physics
1 answer:
babymother [125]3 years ago
6 0

Answer:

Explanation:

height of pole = 15 ft

height of man = 6 ft

Let the length of shadow is y .

According to the diagram

Let at any time the distance of man is x.

The two triangles are similar

\frac{y-x}{y}=\frac{6}{15}

15 y - 15 x = 6 y

9 y = 15 x

y=\frac{5}{3}x

Differentiate with respect to time.

\frac{dy}{dt}=\frac{5}{3}\frac{dx}{dt}

As given, dx/dt = 4 ft/s

\frac{dy}{dt}=\frac{5}{3}\times 4

\frac{dy}{dt}=\frac{20}{3} ft/s

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Benjamin Franklin has convinced his hapless assistant Mike Piepan to participate in an experiment on electiricty. Ben has set up
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Answer:

Mike will receive an electric shock

Explanation:

Human body is a conductor of electricity. When lightning strikes rod and give it negative charge, the rod will dissipate its charge as soon as it comes in contact with earth via conduting material. Mike will receive a severe electric shock as negatice charge pass through his body to other rod and to the ground.His body will feel numb. He may also get unconscious.

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How many electron shells does an atom of oxygen have? (A.) 1 (B.) 2 (C.) 3 (D.) 4
Vladimir79 [104]
It has two electrons
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Photons of wavelength 65.0 pm are Compton-scattered from a free electron which picks up a kinetic energy of 0.84 keV from the co
ElenaW [278]

Answer:

λ  = 65.6 pm

Explanation:

Given that

λo = 65 pm

The initial energy of the electron

E_o=\dfrac{hC}{\lambda_0 }

Now by putting the values

E_o=\dfrac{hC}{\lambda_0 }

E_o=\dfrac{6.67\times 10^{-34}\times 3\times 10^8}{65\times 10^{-12}}

E_o=3.05\times 10^{-15}\ J

E_o=\dfrac{3.05\times 10^{-15}}{1.6\times 10^{-19}\times 10^3}\ KeV

Eo=19.06 KeV

Given that kinetic energy KE= 0.84 KeV

Therefore the final energy

E= Eo - KE

E = 19.06 - 0.84 KeV

E= 18.22 KeV

The wavelength  λ can be find as

E=\dfrac{hC}{\lambda}

\lambda=\dfrac{hC}{E}

\lambda=\dfrac{6.67\times 10^{-34}\times 3\times 10^8}{19.06 \times 10^3\times 1.6\times 10^{-19}}

λ = 6.56 x 10⁻¹¹ m

λ  = 65.6 pm

3 0
3 years ago
A device for training astronauts and jet fighter pilots is designed to rotate the trainee in a horizontal circle of radius 11.0
kvv77 [185]

The velocity of the trainee is 29 m/s or 0.42 rev/s

<h3>Further explanation</h3>

Acceleration is rate of change of velocity.

\large {\boxed {a = \frac{v - u}{t} } }

\large {\boxed {d = \frac{v + u}{2}~t } }

<em>a = acceleration (m / s²)v = final velocity (m / s)</em>

<em>u = initial velocity (m / s)</em>

<em>t = time taken (s)</em>

<em>d = distance (m)</em>

Centripetal Acceleration of circular motion could be calculated using following formula:

\large {\boxed {a_s = v^2 / R} }

<em>a = centripetal acceleration ( m/s² )</em>

<em>v = velocity ( m/s )</em>

<em>R = radius of circle ( m )</em>

Let us now tackle the problem!

<u>Given:</u>

Radius of horizontal circle = R = 11.0 m

Force Felt by the Trainee = F = 7.80w

<u>Unknown:</u>

Velocity of Rotation = v = ?

<u>Solution:</u>

F = ma

F = m\frac{v^2}{R}

7.80w = m\frac{v^2}{R}

7.80mg = m\frac{v^2}{R}

7.80g = \frac{v^2}{R}

7.80 \times 9.8 = \frac{v^2}{11.0}

v^2 = 840.84

v \approx 29 ~m/s

\omega = \frac{v}{R}  → in rad/s

\omega = \frac{v}{2 \pi R}  → in rev/s

\omega = \frac{29}{2 \pi \times 11.0}

\omega \approx 0.42 ~ rev/s

<h3>Learn more</h3>
  • Velocity of Runner : brainly.com/question/3813437
  • Kinetic Energy : brainly.com/question/692781
  • Acceleration : brainly.com/question/2283922
  • The Speed of Car : brainly.com/question/568302
  • Uniform Circular Motion : brainly.com/question/2562955
  • Trajectory Motion : brainly.com/question/8656387

<h3>Answer details</h3>

Grade: High School

Subject: Physics

Chapter: Circular Motion

Keywords: Velocity , Driver , Car , Deceleration , Acceleration , Obstacle , Speed , Time , Rate , Circular , Ball , Centripetal

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Silt and other wash can accumulate behind the motor and if other boats are added they can get their hulls damaged or scraped then, depending on the size of the material. It can also cause trailers to get stuck if they drive into the place from where the boat came.
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