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3 years ago

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An athlete is running a 5-km race at an average speed of 8 km/h. She has to stop to tie her shoe. After tying her shoe, she cont

inues running at 8 km/h. Why would her average speed for the entire race be less than 8 km/h?

1 answer:

Ray Of Light [21]3 years ago

5 0

The total time she took to complete the race increased

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A 92.0-kg skydiver falls straight downward with an open parachute through a vertical height of 325 m. The skydiver's velocity re

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Answer: Workdone293.02KJ

Explanation: The equation to use to calculate Workdone = Change in KE + Change in PE

Assuming velocity is constant,KE becomes 0

Workdone= Change in PE=mg

W=92×9.8×325=293.02KJ

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4 years ago

A 4 kg block is moving at 12 m/s on a horizontal frictionless surface. a constant force is applied such that the block slows wit

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Answer:

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Explanation:

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3 years ago

Find an expression for the electric field E⃗ at the center of the semicircle. Hint: A small piece of arc length Δs spans a small

Hatshy [7]

Answer:

Electric Field a the centre $E=\dfrac{Q}{2\pi^2\epsilon_0 R^2}(-\vec j)$

Explanation:

<u>Given:</u>

Total charge on the semicircle =Q

Radius of the semicircle=R

Let consider a elemental charge on the semicircle at an angle $\theta\\$ with the horizontal. Since the The charge distribution is symmetrical about y axis so the there will symmetrical charge on other side. The horizontal component will cancel out each other and vertical component will get added so let dE be the electric Field due to elemental charge

Let $\lambda$ be the charge per unit length such that $\lambda=\dfrac{Q}{\pi R}$

$k=\dfrac{1}{4\pi \epsilon_0}$

Total Electric Field at the centre

$=2dE\sin\theta\\=2\dfrac{k\lambda }{R}\int \sin \theta d\theta\\$

integrating 0 to $\dfrac{\pi}{2}$

$E=\dfrac{2k\lambda}{R}(-\vec j)$

$E=\dfrac{Q}{2\pi^2\epsilon_0 R^2}(-\vec j)$

So the Electric field at the centre is calculated.

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3 years ago

What are the steps to form a igneous rock

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Answer:

igneous rocks are formed through the cooling and solidification of magma or lava. As hot, molten rock rises to the surface, it undergoes changes in temperature and pressure that cause it to cool, solidify, and crystallize.

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3 years ago

The pencil has a shadow. is the pencil opaque or transparent?

Alborosie

Explanation:

Pencil is clearly an opaque object because, we cannot see through it. For example, take a pencil in your front. You will observe that, you are not able to see the objects behind it. And that is why you can say that pencil is an opaque object.

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3 years ago

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