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3 years ago

When do you think did the present day humans first appeared on earth?

2 answers:

8 0

The present day humans first appeared in the fossil record's around 66 million years ago soon after the cretaceous paleogene extinction event that eliminated 3 - quarters of plant and animals species on earth including many dinosaurs.

LenKa [72]3 years ago

6 0

ALL of the present day humans had to appear on Earth for the first time all within roughly the past 100 or 110 years.

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A student sits at rest on a piano stool that can rotate without friction. The moment of inertia of the student-stool system is 4

irina [24]

Here We can use principle of angular momentum conservation

Here as we know boy + projected mass system has no external torque

Since there is no torque so we can say the angular momentum is conserved

$mvL = (I + mL^2)\omega$

now we know that

m = 2 kg

v = 2.5 m/s

L = 0.35 m

I = 4.5 kg-m^2

now plug in all values in above equation

$2\times 2.5 \times 0.35 = (4.5 + (2\times 0.35^2))\omega$

$1.75 = [4.5 + 0.245]\omega$

$1.75 = 4.745\omega$

$\omega = 0.37 rad/s$

so the final angular speed will be 0.37 rad/s

4 0

3 years ago

Lab report 1.04 hypothesis

Zanzabum

Answer:a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Hope This helps!!

5 0

3 years ago

answers At the beginning of 2019, Robotics Inc. acquired a manufacturing facility for $12.3 million. $9.3 million of the purchas

pshichka [43]

Answer:

$613,077

Explanation:

Calculation for the depreciation on the building for 2021

First step is to calculate the depreciation expense for the year 2019 and 2020 using this formula

Depreciation expense = (Purchase price - Residual value) ÷ (Useful life)

Let plug in the formula

Depreciation expense= ($9,300,000 - $1,300,000) ÷ (20 years)

Depreciation expense= ($8,000,000) ÷ (20 years)

Depreciation expense= $400,000

Second step is to calculate the book value for the year 2021 using this formula

Book value = Purchase price - Depreciation expenses *2 years

Let plug in the formula

Book value= $9,300,000 - $400,000 × 2

Book value= $8,500,000

Last step is to calculate the depreciation for 2021 using this formula

2021 Depreciation=(Book value-Residual value)÷Useful life

2021 Depreciation= ($8,500,000 - $530,000) ÷ (15 years - 2 years)

2021 Depreciation=$7,970,000÷13 years

2021 Depreciation= $613,077

Therefore the depreciation on the building for 2021 will be $613,077

8 0

3 years ago

What unit is used to measure loudness and at what level can hearing loss happen?

valkas [14]

Decibel (dB) and, hearing loss levels can be anywhere like -56 to -70 dB for Moderate/severe hearing loss, -71 to -90 dB for Severe loss and -91 dB for Profound loss.

6 0

3 years ago

Water vapor can react reversibly with solid carbon to yield a mixture of hydrogen gas and carbon monoxide. Suppose you continual

umka2103 [35]

Answer:

Product side

Explanation:

When water vapor reacts reversibly with solid carbon to yield a mixture of hydrogen gas and carbon monoxide and we continually add more water vapor to the reaction the equilibrium of the reaction shifts to the product side.

Because gaseous water is reactant that appears in the reaction quotient expression.

$H_{2}O+ C_{s}\leftrightharpoons H_{2}_{g}+ CO$

When we add more water vapor to the reaction the product formation is increased. The reaction goes in forward direction affecting the equilibrium.

3 0

3 years ago