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liberstina [14]
3 years ago
5

Two children who are bored while waiting for their flight at the airport decide to race from one end of the 20-m-long moving sid

ewalk to the other and back. Phillippe runs on the sidewalk at 2.0 m/s (relative to the sidewalk). Renee runs on the floor at 2.0 m/s. The sidewalk moves at 1.5 m/s relative to the floor. Both make the turn instantly with no loss of speed. a. Who wins the race
Physics
2 answers:
QveST [7]3 years ago
8 0

Answer: Phillipe wins the race

Explanation:

Given

Length of track=20 m

Velocity of Phillippe=2 m/s w.r.t sidewalk

Velocity of sidewalk=1.5 m/s

Rena velocity=2 m/s

Therefore absolute velocity of P is 2+1.5=3.5 m/s

Time taken by phillippe \frac{20}{3.5}+\frac{20}{3.5-1.5}

t_P=5.714+10=15.714 s

Time taken by rena

t_r=\frac{20}{2}+\frac{20}{2}=20 s

as the time taken  by phillippe is less than rena therefore Phillippe wins the race.

Usimov [2.4K]3 years ago
4 0

Answer:

Renee will win the race

Explanation:

Total time of motion for Phillippe is given as

t_1 = \frac{L}{v + v_1 } + \frac{L}{v - v_1}

now we have

t_1 = \frac{L}{2 + 1.5} + \frac{L}{2 - 1.5}

t_1 = \frac{L}{3.5} + \frac{L}{0.5}

t_1 = 2.28 L

now for Renee we have

t_2 = \frac{L}{2} + \frac{L}{2}

t_2 = L

so here we can see that

t_2 < t_1

so Renee will win the race

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If the energies sound in the device is microphone what is the energy out
Katen [24]

Answer:

Microphones are a type of transducer - a device which converts energy from one form to another. Microphones convert acoustical energy (sound waves) into electrical energy (the audio signal). Different types of microphone have different ways of converting energy but they all share one thing in common: The diaphragm.

Explanation:

5 0
3 years ago
During a hurricane in 2008, the Westin Hotel in downtownNew Orleans suffered damage. Suppose a piece of glass dropped near the t
tangare [24]

Answer:

  • <u>77.8 m/s, downward</u>

Explanation:

For uniform acceleration motion, the average speed is equal to half the soum of the initial velocity, Vi, and the final velocity, Vf

  • Average speed = (Vf + Vi)/2

Also, by definition, the average speed is the distance divided by the time:

  • Average speed = distance / time

Then:

  • (Vf + Vi)/2 = 300m/6.62s

Other kinematic equation for uniform acceleration is:

  • Vf = Vi + a×t

Since the window is falling and the air resistance is ignored, a = g (gravitational acceleration ≈ 9.8m/s²)

Replacing the known values we can set a system of two equations:

From (Vf + Vi)/2 = 300m/6.62s

(Vf + Vi) = 2 × 300m/6.62s

  • Vf + Vi = 90.634      equation 1

From Vf = Vi + a×t

Vf - Vi = 9.8 (6.62)

  • Vf - Vi = 64.876     equation 2

Adding the two equations:

  • 2Vf = 155.510

  • Vf = 77.8 m/s downward (velocities must be reported with their directions)
8 0
3 years ago
A ball is dropped from an aircraft flying at an altitude of 8,848 meters assuming gravity is 9.8m/s what is the total amount of
Dafna11 [192]
In this question, you're determining the time (t) taken for an object to fall from a distance (d).

The equation to represent this is:
Time equals the square root of 2 times the distance divided by the gravitational force of earth.
In equation from it looks like this (there isn't an icon to represent square root so just pretend like there's a square root there):
t = 2d/g (square-rooted)

d = 8,848m and g = 9.8m/s

Now plug in the information we have:
t = 2 x 8,848m/9.8m/s (square-rooted)

The first step is to multiply 2 times 8,848m:
t = 17,696m/9.8m/s (square-rooted)

Now divide 9.8m/s by 17,696m (note that the two m's (meters) cancels out leaving you with only s (seconds):
t = 1805.72s (square-rooted)

Now for the last step, find the square root of the remaining number:
t = 42.5s

So the time it takes the ball to drop from the height (distance) of 8,848 meters, and falling with the gravitational pull of 9.8 meters per second is 42.5 seconds.

I hope this helps :)

7 0
3 years ago
calculate the diameter of a silver wire of length 75cm , which is extended by 1.85mm when a 10kg mass is suspended from it's end
sdas [7]

Answer:0.8\ mm

Explanation:

Given

length of wire l=75\ cm

change in length \Delta l=1.85\ mm

mass of wire m=10\ kg

Young's modulus for silver E=7.9\times 10^{10}\ N/m^2

load on wire F=mg

F=10\times 9.8=98\ kg

change in length is given by

\Delta l=\dfrac{Pl}{AE}

Where A=area of cross-section

A=\dfrac{Pl}{\Delta lE}

A=\dfrac{98\times 0.75}{1.85\times 10^{-3}\times 7.9\times 10^{10}}

A=\dfrac{73.5}{14.615\times 10^{7}}

A=5.029\times 10^{-7}\ m^2

also wire is the shape of cylinder so cross-section is given by

A=\dfrac{\pi d^2}{4}=5.029\times 10^{-7}\ m^2

\Rightarrow d^2=\dfrac{5.029\times 10^{-7}\times 4}{\pi }

\Rightarrow d^2=64.02\times 10^{-8}

\Rightarrow d=8\times 10^{-4}\ m

\Rightarrow d=0.8\ mm

4 0
3 years ago
If a fast-moving car making a loud noise approaches and moves past the person, what will happen as the distance between the two
Mrac [35]
The Car Will Cause Some Kind Of Wind Wave And Hit The Person's Body But Its Not Harmful And You Will Hear The Loud Noise Passing By

5 0
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