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3 years ago

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an athlete runs 5.4 laps around a circular track that is 400.0 m long. If this takes 540 s, what is the average velocity of the

athlete? What is the average speed of the athlete over the complete distance of the run?

1 answer:

Slav-nsk [51]3 years ago

6 0

Answer:

Average velocity is 0.296 m/s.

Average speed is 4.0 m/s.

Explanation:

Given:

Distance of the circular track is, $D=400.0\ m$

Number of laps ran is, $n=5.4$

Time taken for the run is, $t=540\ s$

Now, total distance covered in 5.4 laps = $D_T=D\times n=400\times 5.4=2160\ m$

Also, since the path is a circle, the final position of the athlete after 5.4 laps will be 0.4 of 400 m ahead of the starting point.

Distance covered in 0.4 laps is, $\textrm{Displacemet}=0.4\times 400=160\ m$

Therefore, the displacement of the athlete will be 160 m as the athlete is 160 m ahead of the starting point and displacement depends on the initial and final points only.

Now, average velocity is given as:

$v_{avg}=\frac{\textrm{Displacemet}}{t}=\frac{160}{540}=0.296\ m/s$

Average speed is the ratio of total distance covered to total time taken.

So, average speed = $\frac{D_T}{t}=\frac{2160}{540}=4\ m/s$

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2 years ago

A stretched spring has 5184 J of elastic potential energy and a spring constant of 16,200 N/m. What is the displacement of the s

yawa3891 [41]

Hello!

A stretched spring has 5184 J of elastic potential energy and a spring constant of 16,200 N/m. What is the displacement of the spring ?

Data:

$E_{pe}\:(elastic\:potential\:energy) = 5184\:J$

$K\:(constant) = 16200\:N/m$

$x\:(displacement) =\:?$

For a spring (or an elastic), the elastic potential energy is calculated by the following expression:

$E_{pe} = \dfrac{k*x^2}{2}$

Where k represents the elastic constant of the spring (or elastic) and x the deformation or displacement suffered by the spring.

Solving:

$E_{pe} = \dfrac{k*x^2}{2}$

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$x^{2} = \dfrac{10368}{16200}$

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$x = \sqrt{0.64}$

$\boxed{\boxed{x = 0.8\:m}}\end{array}}\qquad\checkmark$

Answer:

The displacement of the spring = 0.8 m

_______________________________

I Hope this helps, greetings ... Dexteright02! =)

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3 years ago