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3 years ago

Humans first appeared during the _____.

2 answers:

8 0

<span>Humans first appeared during the Quaternary period. <span>The Quaternary or Neozoic period develops in the Cenozoic era, which extends from 2,588 million years ago to the present. The Quaternary is divided into two periods. The Pleistocene, the first and longest period of the period, was characterized by the cycles of glaciations and the appearance of the first humans (homos habilis); this period extended from 2,588 million years to 10,000 years BC The Holocene, the second epoch of the period, was characterized by the end of the glaciation and the emergence of human civilization; this period extends from 10,000 years BC to the present.</span></span>

sergeinik [125]3 years ago

6 0

your answer is Quaternary period

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A train starts from rest and travels for 5.0 s with a uniform acceleration of 1.5 m/s2. What is the final velocity of the train?

alexandr1967 [171]

Answer:

Final speed of the train is 7.5 m/s

Explanation:

It is given that,

Uniform acceleration of the train is, a = 1.5 m/s²

It starts from rest and travels for 5.0 s. We have to find the final velocity of the train. By using first equation of motion as :

$v=u+at$

Here, train starts from rest so, u = 0

$v=0+1.5\ m/s^2\times 5\ s$

v = 7.5 m/s

So, the final velocity of the train is 7.5 m/s. Hence, this is the required solution.

7 0

3 years ago

Read 2 more answers

Consider a river flowing toward a lake at an average speed of 3 m/s at a rate of 550 m3/s at a location 58 m above the lake surf

Vladimir [108]

Answer:

1. 0.574 kJ/kg

2. 315.7 MW

Explanation:

1. The mechanical energy per unit mass of the river is given by:

$E_{m} = E_{k} + E_{p}$

$E_{m} = \frac{1}{2}v^{2} + gh$

Where:

Ek is the kinetic energy

Ep is the potential energy

v is the speed of the river = 3 m/s

g is the gravity = 9.81 m/s²

h is the height = 58 m

$E_{m} = \frac{1}{2}(3 m/s)^{2} + 9.81 m/s^{2}*58 m = 0.574 kJ/Kg$

Hence, the total mechanical energy of the river is 0.574 kJ/kg.

2. The power generation potential on the river is:

$P = m(t)E_{m} = \rho*V(t)*E_{m} = 1000 kg/m^{3}*550 m^{3}/s*0.574 kJ/kg = 315.7 MW$

Therefore, the power generation potential of the entire river is 315.7 MW.

I hope it helps you!

4 0

3 years ago

Object A has a mass of 100 grams. Object B has a mass of 150 grams. They are both traveling at the same velocity. What can you c

Scilla [17]

-- Momentum is (mass) x (speed).
Object B has 1.5 times as much momentum as Object A has.

-- Kinetic energy is (1/2) x (mass) x (speed) .
Object B has 1.5 times as much kinetic energy as Object A has.

-- If they would both stop long enough to get on the scale,
Object B would weigh 1.5 times as much as Object A does.

8 0

3 years ago

an object of mass m is traveling at constant speed v in a circular path of radius r. how much work is done by the centripetal fo

vlada-n [284]

The work done is by the centripetal force on mass m during an angular displacement of 2π revolutions mv²2π /r J

Centripetal force - a force acts on an moving object in circular path.

the centripetal force is given by

F= mv²/r (equation1)

Work done is given by

W = Fd (equation 2)

d = 2π

work is done by the centripetal force on mass m during an angular displacement of 2π revolutions is given by:

to calculate work done using equation 1 in 2 we get

W = mv² d/r

W = mv² × 2π /r J

The work done is by the centripetal force on mass m during an angular displacement of 2π revolutions mv²2π /r J

To know more about centripetal force :

brainly.com/question/13031430

#SPJ4

6 0

1 year ago

Assume a solar cell would produce a current of 500mA and 3 V. What is the power of this solar cell?

defon

Answer:

the power of the solar cell is 1.5 watts

Explanation:

Recall that power is defined as the product of the voltage (V) times the running current (I): Power = V * I.

The only thing we have to take care of before actually performing the operation, is to convert milliamps into Amps, so our answer comes directly in the appropriate units (Watts). 500 mAmps can be written as 0.5 Amps, then, the product becomes:

Power = V * I = 3 V * 0.5 Amps = 1.5 watts

8 0

3 years ago