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3 years ago

What is the approximate percentage of geologic time that humans have existed on earth since its origin?

Physics

1 answer:

Alekssandra [29.7K]3 years ago

5 0

Answer:about 200,000 years ago that humans existed on earth.

Explanation:Geologic time refers to the planet's changing geology. The earliest fossils of modern humans are from the middle Paleolithic about 200,000 years ago such as the omo remains from Ethiopia and the fossil of herto classified equally as homosapiens equally from Ethiopia.

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An object is attached to a vertical spring and bobs up and down between points a and

Anton [14]

it would be at either A or B.

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3 years ago

If the mass of the object is doubled and the speed is halved then kinetic energy will change by a factor of:

Orlov [11]

I could be wrong but I believe it’s 1/2

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3 years ago

A uniform solid disk with a mass of 24.3 kg and a radius of 0.364 m is free to rotate about a frictionless axle. Forces of 90.0

a_sh-v [17]

Answer:

a. $-12.7 Nm$

b. $-7.9 rad/s^2$

Explanation:

I have attached an illustration of a solid disk with the respective forces applied, as stated in this question.

Forces applied to the solid disk include:

$F_1 = 90.0N\\F_2 = 125N$

Other parameters given include:

Mass of solid disk, $M = 24.3kg$

and radius of solid disk, $r = 0.364m$

a.) The formula for determining torque ( $T$ ), is $T = r * F$

Hence the net torque produced by the two forces is given as a summation of both forces:

$T = T_{125} + T_{90}\\= -r(125)sin90 + r(90)sin90\\= 0.364(-125 + 90)\\= -12.7 Nm$

b.) The angular acceleration of the disk can be found thus:

using the formula for the Moment of Inertia of a solid disk;

$I_{disk} = {\frac{1}{2}}Mr^2$

where $M$ = Mass of solid disk

and $r$ = radius of solid disk

We then relate the torque and angular acceleration ( $\alpha$ ) with the formula:

$T = I\alpha \\-12.7 = ({\frac{1}{2}}Mr^2)\alpha \\\alpha = -{\frac{12.7}{1.61}} = -7.9 rad/s^2$

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4 years ago

Where does most star formation occur in the milky way galaxy?

k0ka [10]

Answer:

Star formation occurs most rapidly in the spiral arms, where the density of interstellar matter is highest.

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2 years ago

A light wave passes through an aperture (that is, a narrow slit). When it does so, the degree to which the wave spreads out will

crimeas [40]

Explanation:

Single slit diffraction

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3 years ago