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Artist 52 [7]
3 years ago
10

Melissa and Rory live near a bike trail, 21 km apart. They plan to meet at a park mid-way between their homes. They start from t

heir homes at the same moment, and ride toward each other. Both ride at 7 km/hour. Melissa’s dog Jessie knows this routine. He starts with Melissa, and runs at 18 km/hour toward Rory. When he reaches Rory, he turns around and runs toward Melissa. He reaches Melissa, turns around and runs toward Rory again, and so on, until Melissa and Rory meet. How many kilometers did Jessie run?
Physics
1 answer:
DiKsa [7]3 years ago
7 0

Answer:

27km.

Explanation:

Jessie will run for a duration of time, which is the time it takes for Melissa and Rory to meet each other.

Together combined, Melissa and Rory runs at 14km/h. The bike trail is 21km, so it will take 1.5 hours.

Jessie runs at 18km/h, so Jessie will run 18 * 1.5 = 27km.

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klasskru [66]
Refer to the diagram shown below.

In order for the balloon to strike the professor's head, th balloon should drop by 18 - 1.7 = 16.3 m in the time at the professor takes to walk 1 m.
The time for the professor to walk 1 m is
t = (1 m)/(0.45 m/s) = 2.2222 s

The initial vertical velocity of the balloon is zero.
The vertical drop of the balloon in 2.2222 s is
h = (1/2)*(9.8 m/s²)*(2.2222 s)² = 24.197 m

Because 24.97 > 16.3, the balloon lands in front of the professor, and does not hit the professor.

The time for the balloon to hit the ground is
(1/2)*(9.8)*t² = 18
t = 1.9166 s

The time difference is 2.2222 - 1.9166 = 0.3056 s
Within this time interval, the professor travels 0.45*0.3056 = 0.175 m
Therefore the balloon falls 0.175 m in front of the professor.

Answer: 
The balloon misses the professor, and falls 0.175 m in front of the professor.

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3 years ago
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If I drop my egg unprotected, then it will break.
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what principle is responsible for alternating light and dark bands when light passes through two or more narrow slits?
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The superposition principle is responsible for alternating light and dark bands when light passes through two or more narrow slits.

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The fact that the two waves' crests follow different paths ensures that they do. A distinctive pattern of brilliant and dark fringes is seen when monochromatic light illuminates a distant screen after passing through two small openings. The superposition of overlapping light waves coming from the two slits results in this interference pattern.

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1 year ago
If 1.00 mol of argon is placed in a 0.500-L container at 28.0 ∘C , what is the difference between the ideal pressure (as predict
Rudik [331]

Answer:

1.98 atm

Explanation:

Given that:

Temperature = 28.0 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T₁ = (28 + 273.15) K = 301.15 K

n = 1

V = 0.500 L

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L atm/ K mol  

Applying the equation as:

P × 0.500 L = 1 ×0.0821 L atm/ K mol  × 301.15 K

⇒P (ideal) = 49.45 atm

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\left(P+\frac{an^2}{V^2}\right)\left(V-nb\right)=nRT

R = 0.0821 L atm/ K mol  

Where, a and b are constants.

For Ar, given that:

So, a = 1.345 atm L² / mol²

b =  0.03219 L / mol

So,  

\left(P+\frac{1.345\times \:1^2}{0.500^2}\right)\left(0.500-1\times 0.03219\right)=1\times 0.0821\times 301.15

P+\frac{1.345}{0.25}=\frac{24.724415}{0.46781}

P=\frac{24.724415}{0.46781}-\frac{1.345}{0.25}

⇒P  (real) = 47.47 atm

Difference in pressure = 49.45 atm - 47.47 atm = 1.98 atm

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