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3 years ago

PLEASE HELP. HOW DO U CALCULATE??

Physics

1 answer:

tatyana61 [14]3 years ago

5 0

-- The energy of one photon is (h · frequency of the light)

' h ' is 6.626 × 10⁻³⁴ m²-kg/s ("Planck's Constant")

-- The question doesn't tell you the frequency of the light from the LED, but it tells you the wavelength, and

Frequency = (speed of light) / (wavelength) .

-- Now you have everything you need to calculate the energy carried by one photon from the LED.

-- The power of the light from the LED is 120 milliwatts. That's 0.120 Joule of energy per second.

Now you should be able to find the number of photons per second. It's going to be (0.120 Joule) / (energy carried by one photon) .

When I scribbled it out on a scrap of scratch paper, I got 3.853 x 10³⁸ photons, but you'd better really check that out.

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3 years ago

A man and his dog are “walking” on flat Street. He is pulling on his stubborn dog with a force of 70 N Directed at a 30° angle f

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Answer:

X component of force is 60.62 N.

Y component of force is 35 N.

Force of gravity on the dog is 245 N.

Magnitude of normal force is 210 N.

Explanation:

Given:

Force of pull is, $F=70\ N$

Mass of the dog is, $m=25\ kg$

Angle of inclination is, $\theta =30$ °

Acceleration due to gravity is, $g=9.8\ m/s^2$

The free body diagram of the dog is shown below.

The X and Y components of force of pull is given as:

$F_X=F\cos \theta=(70)\cos (30)=60.62\ N\\F_Y=F\sin \theta=(70)\sin(30)=35\ N$

Therefore, the X and Y components of the force are 60.62 N and 35 N respectively.

Force of gravity on the dog is the product of its mass and acceleration due to gravity. Thus,

$F_g=mg=25\times 9.8=245\ N$

Therefore, the force of gravity on the dog is 245 N.

Now, consider the motion in the vertical direction of the dog. As there is no motion in the vertical direction, the net force along the Y direction is 0. In other words, the total Upward force is equal to the total downward force.

From the free body diagram,

$N+F_Y=mg\\N=mg-F_Y\\N=245-35=210\ N$

Therefore, the normal force acting on the dog is 210 N.

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3 years ago

Please help me 5-11 help help

Illusion [34]

Your answer is -6 did that answer your question

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