3 years ago

Suppose a runner completes one lap around a 400-m track in a time of 50 s. Calculate the average speed of the runner.

Physics

1 answer:

suter [353]3 years ago

6 0

Answer:

8m/s

Explanation:

Average Speed = distance / time = 400/50 = 8m/s

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How far can a person run in 15 minutes if he or she runs at an average speed of 16 km/hr

Studentka2010 [4]

4 km/hr. There are four quarters in an hour, so just divide 16 by 4 and you get 4. It is directly proportional.

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You are riding your bike to the mall. You travel the first mile in ten minutes. The last mile takes you 15 minutes. This is an e

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A cyclist intends to cycle up a 7.70o hill whose vertical height is 126m. Assuming the mass of bicycle plus person is 75.0kg, ca

Ksivusya [100]

Answer:

92704.5 J

596.44737 N

Explanation:

m = Mass of person + bicycle = 75 kg

g = Acceleration due to gravity = 9.81 m/s²

h = Vertical height = 126 m

$\theta$ = Angle = 7.7°

d = Diameter = 0.388 m

Work done against gravity is given by

$P=mgh\\\Rightarrow P=75\times 9.81\times 126\\\Rightarrow P=92704.5\ J$

Work done is 92704.5 J

Force required is given by

$F=\dfrac{mgrsin\theta}{\pi d}\\\Rightarrow F=\dfrac{75\times 9.81\times sin7.7\times 5.12}{\pi\times 0.388}\\\Rightarrow F=596.44737\ N$

The force is 596.44737 N

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Calculate the vapor pressure for a mist of spherical water droplets of radius 3.70×10−8m surrounded by water vapor at 298 K. The

poizon [28]

Answer:

The vapor pressure for a mist is $P= 25.92\ Torr$

Explanation:

From the question we are given that

The radius is $r = 3.70 *10^{-8} m$

The temperature is $T = 298K$

The vapor pressure of water $P_o = 25.2\ Torr$

The density of water is $\rho = 998 kg.m^{-3}$

The surface tension of water is $\sigma = 71.99 m N \cdot m^{-1}$

Generally the equation of that is mathematically represented as

$ln (\frac{P}{P_0} ) = \frac{2 \sigma M}{r \rho RT}$

Where P is the vapor pressure for mist

R is the ideal gas constant = 8.31

making P the subject in the formula

$P = e^ {\frac{2 \sigma M}{r \rho RT}} * P_0$

$= e^{\frac{2 *(0.07199)(0.018)}{(3.70*10^{-8})(998)(8.31)(298)} } * 25.2$

$P= 25.92Torr$

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3 years ago