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2 years ago

A young athlete has a mass of 42 kg. On a day when there is no wind she runs a 100m race in 14.2

Physics

1 answer:

Cloud [144]2 years ago

3 0

Answer:

7 m/s approx

Explanation:

Step one:

Given data

Mass m= 42kg

distance covered= 100m

time taken = 14.2 seconds

Required

The speed of the athlete

Step two:

We know that speed= distance/time

Substitute

Speed= 100/14.2

Speed= 7.04 m/s

Speed= 7 m/s approx

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A mixture of nitrogen and xenon gases, at a total pressure of 836 mm Hg, contains 2.80 grams of nitrogen and 24.9 grams of xenon

larisa86 [58]

Answer: Partial pressure of nitrogen and xenon are 288mmHg and 548 mmHg respectively.

Explanation:

The partial pressure of a gas is given by Raoult's law, which is:

$p_A=p_T\times \chi_A$

where,

$p_A$ = partial pressure of substance A

$p_T$ = total pressure

$\chi_A$ = mole fraction of substance A

We are given:

$m_{N_2}=2.80g$

$m_{Xe}=24.9g$

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

And,

$n_A=\frac{m_A}{M_A}$

Mole fraction of nitrogen is given as:

$\chi_{N_2}=\frac{\frac{m_{N_2}}{M_{N_2}}}{(\frac{m_{N_2}}{M_{N_2}}+\frac{m_{Xe}}{M_{Xe}})}$

Molar mass of $N_2$ = 28 g/mol

Molar mass of $Xe$ = g/mol

Putting values in above equation, we get:

$\chi_{N_2}=\frac{\frac{2.80}{28}}{\frac{2.80}{28}+\frac{24.9}{131}}$

$\chi_{N_2}=\frac{0.100}{0.100+0.190}=0.345$

To calculate the mole fraction of xenon, we use the equation:

$\chi_{Xe}+\chi_{N_2}=1\\\\\chi_{Xe}=1-0.345=0.655$

$p_{N_2}=836mmHg\times 0.345=288mmHg$

$p_{Xe}=836mmHg\times 0.655=548mmHg$

Thus partial pressure of nitrogen and xenon are 288mmHg and 548 mmHg respectively.

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igor_vitrenko [27]

Answer:

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3 years ago

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You’ve set up a frictionless car racetrack, with a loop of radius 0.5 m. Your toy car of mass 2 kg starts at rest at the top of

Anna007 [38]

Answer

h = 1.12 m

Explanation:

given,

mass of the car = 2 kg

radius = 0.5 m

let h be the height of the ramp