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2 years ago

Which runner has greater kinetic energy: a 45 kg runner moving at a speed of 7 m per second or a 93 kg runner moving at a

Physics

1 answer:

bagirrra123 [75]2 years ago

7 0

Kinetic Energy = (1/2) (mass) (speed)

First runner: KE = (1/2) (45kg) (49 m/s) = 1,102.5 Joules

Second runner: KE = (1/2) (93kg) (9 m/s) = 418.5 Joules

The <em>first runner </em><em>has 163</em>% more kinetic energy than the second runner has.

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At one point in space the Electric potential is measured to be 119 V at a distance of 1 meters away it is measured to be 43 V. F

Anni [7]

Answer:

76 V/m

Explanation:

$V_{i}$ = Electric potential at initial location = 119 V

$V_{f}$ = Electric potential at final location = 43 V

$d$ = distance between initial and final location = 1 m

$E$ = magnitude of electric field

Magnitude of electric field is given as

$E = \frac{- (V_{f} - V_{i})}{d}$

$E = \frac{- (43 - 119)}{1}$

$E$ = 76 V/m

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3 years ago

Choose ALL that apply

Keith_Richards [23]

The answers a a,b, and d

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2 years ago

A rock is thrown upward from level ground in such a way that the maximumheight of its flight is equal to its horizontal rangeR.

Snowcat [4.5K]

A) The vertical component of velocity v is taking the rock to a height

Vertical component = $vsin\theta$
The time taken to reach maximum height = $\frac{vsin\theta}{g}$
So total time of rocks flight = $\frac{2vsin\theta}{g}$
Range of rock is due to the horizontal component of velocity = $vcos\theta$
Range = $\frac{2*v*sin\theta*v*cos\theta}{g}$ = $\frac{2*v^2*sin\theta*cos\theta}{g}$
Maximum height = $\frac{g*t^2}{2}$ = $\frac{v^2*sin^2\theta}{2*g}$
Since range = maximum height
We have $\frac{2*v^2sin\theta*cos\theta}{g} = \frac{v^2*sin^2\theta}{2*g}$
$tan\theta = 4$
$\theta = 75.96^0$
So when angle of projection is $\theta = 75.96^0$ range is equal to maximum height reached.
b) We have range = $\frac{2*v^2*sin\theta*cos\theta}{g}$ = $\frac{2*v^2*sin2\theta}{g}$
Maximum of range is reached when $\theta = 45^0$
Maximum range = $\frac{2*v^2}{g}$
c) For range to be equal to maximum height only condition is $tan\theta = 4$ , it does not depend upon acceleration due to gravity and velocity. That angle is a constant.

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3 years ago

How does natural selection produce change in a population of mice?

sergey [27]

Answer:

The population of the mice will decrease to the faster, stronger, and smarter mice because the weaker will die because of natural selection.

Explanation:

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2 years ago

Which of the following describes resistance force?

Verdich [7]

Force applied by the machine to over come resistance