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Katarina [22]
3 years ago
8

A geologist is studying rock layers in an old river bed, and he finds a fossil of a fish and a horsetail rush in the same rock l

ayer. According to the law of faunal and floral succession, the geologist can assume that the rock containing the fossils may date back as far as the _____.
Cambrian period
Ordovician period
Silurian period
Devonian period

Physics
2 answers:
erastovalidia [21]3 years ago
8 0

The correct answer is Devonian period.

This is known to be the period of fishes which occurred 416 million years ago. It is known to be the fourth period of the Paleozoic Era. Significant events like evolution of first insects and other animals.

The Fishes evolved in the Ordovician era but the horses were found in the Devonian period only.

KonstantinChe [14]3 years ago
6 0
A geologist is studying rock layers in an old river bed, and he finds a fossil of a fish and a horsetail rush in the same rock layer. According to the law of faunal and floral succession, the geologist can assume that the rock containing the fossils may date back as far as the <span>Devonian period</span>.
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An initially stationary object experiences an acceleration of 6 m/s2 for a time of 15 s. How far will it travel during that time
andrew-mc [135]

Answer:

The object will travel 675 m during that time.

Explanation:

A body moves with constant acceleration motion or uniformly accelerated rectilinear motion (u.a.r.m) when the path is a straight line, but the velocity is not necessarily constant because there is an acceleration.

In other words, a body performs a u.a.r.m when its path is a straight line and its acceleration is constant. This implies that the speed increases or decreases uniformly.

In this case, the position is calculated using the expression:

x = xo + vo*t + ½*a*t²

where:

  • x0 is the initial position.
  • v0 is the initial velocity.
  • a is the acceleration.
  • t is the time interval in which the motion is studied.

In this case:

  • x0= 0
  • v0= 0  because the object is initially stationary
  • a= 6 \frac{m}{s^{2} }
  • t= 15 s

Replacing:

x= 0 + 0*15 s + ½*6 \frac{m}{s^{2} }*(15s)²

Solving:

x=½*6 \frac{m}{s^{2} }*(15s)²

x=½*6 \frac{m}{s^{2} }*225 s²

x= 675 m

<u><em> The object will travel 675 m during that time.</em></u>

5 0
2 years ago
A 20 μF capacitor initially charged to 30 μC is discharged through a 1.5 kΩ resistor. Part A How long does it take to reduce the
Natasha_Volkova [10]

Answer:

it will take 36.12 ms to reduce the capacitor's charge to 10 μC

Explanation:

Qi= C×V

then:

Vi = Q/C = 30μ/20μ = 1.5 volts

and:

Vf = Q/C = 10μ/20μ = 0.5 volts

then:

v = v₀e^(–t/τ)  

v₀ is the initial voltage on the cap  

v is the voltage after time t  

R is resistance in ohms,  

C is capacitance in farads  

t is time in seconds  

RC = τ = time constant  

τ = 20µ x 1.5k = 30 ms  

v = v₀e^(t/τ)  

0.5 = 1.5e^(t/30ms)  

e^(t/30ms) = 10/3  

t/30ms = 1.20397

t = (30ms)(1.20397) = 36.12 ms

Therefore, it will take 36.12 ms to reduce the capacitor's charge to 10 μC.

7 0
3 years ago
Which of the following statements is TRUE? The side of the Moon facing away from the Earth is in perpetual darkness. The Moon is
Ivanshal [37]

Answer:

The Moon's distance from the Earth varies during its orbit

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The correct statement is ,The Moon's distance from the Earth varies during its orbit.

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3.Second densest  satellite in solar system.

4.Moon rotates about earth.

5.Moon is an astronomical body .

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