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Citrus2011 [14]
3 years ago
15

Index fossils are used to determine the relative ages of rock and fossils and are also used to

Physics
1 answer:
kolbaska11 [484]3 years ago
3 0

Index fossils are used to determine the relative ages of rock and fossils and are also used to define the boundaries between geologic periods.

<u>Option: A</u>

<u>Explanation:</u>

The fossils which are recognized as fossils guides or indicator fossils are used to classify and recognize geological or faunal periods, termed as index fossils. It must be of short vertical reach, wide geographic distribution and swift patterns in evolution. It helps to assess the rock layers ' age and helps to date other fossils found close and around them. For an instance, Ammonites were abundant in the Mesozoic period between 245 to 65 mya, they have not been found after the Cretaceous era, as they became endangered during the K-T extinction (65 mya).

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The terminal velocity of a person falling in air depends upon the weight and the area of the person facing the fluid.
kolbaska11 [484]

Answer:

The terminal velocity of the diver is 115 m/s = 414 km/hr

Explanation:

At terminal velocity,

Fnet = mg - Fd = 0

Drag force, Fd = cρAv²/2

mg = cρAv²/2

Terminal Velocity of a body falling through a fluid as in a diver falling through air is given by

v = √(2mg/ρcA)

where m = mass of body falling through fluid = 80 kg

g = acceleration due to gravity = 9.8 m/s²

ρ = density fluid, density of air, as obtained from literature = 1.21 kg/m³

c = coefficient of drag friction of diver falling through air, as obtained from literature = 0.7

A = the area of the diver facing the fluid = 0.14 m²

v = √(2mg/ρcA) = √((2 × 80 × 9.8)/(1.21 × 0.7 × 0.14)) = 115 m/s = 115 × (3600/1000) km/hr = 414 km/hr

5 0
3 years ago
How does volcanic ash in earth's atmosphere affect solar radiation?
Irina-Kira [14]

The answer is it increases the amount of solar radiation that is redirected into space. Most of the particles emitted from volcanoes cool the earth by covering entering solar radiation. The cooling result can last for months to years contingent on the features of the eruption.

6 0
3 years ago
Read 2 more answers
A humanoid skeleton is found buried in the ashes of a volcano that erupted between 10,000 and 12,000 years ago. when scientists
Inga [223]
From reliable sources in the internet, the half-live of carbon-14 is given to be 5,730 years. In a span of 10,000 to 12,000 years, there are almost or little more than 2 half-lives. Thus, there should be
                                           A(t) = A(0)(1/2)^t
where t is the number of half-lives, in this case 2. Thus, only about 1/4 of the original amount will be left. 
5 0
3 years ago
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The fast train known as the TGV (Train à Grande Vitesse) that runs south from Paris, France, has a scheduled average speed of 21
andrezito [222]

Answer:

Explanation:

Given

average speed of train(v_{avg})=216 kmph\approx 60 m/s

Maximum acceleration=0.05g

Now centripetal acceleration is

a_c=\frac{v^2}{r}

0.05\times 9.8=\frac{60^2}{r}

r=7346.93 m

(b)Radius of curvature=900 m

therefore a_c=\frac{v^2}{r}

v=\sqrt{a_cr}

v=\sqrt{0.05\times 9.8\times 900}

v=\sqrt{441}=21 m/s

8 0
3 years ago
Two canoeists in identical canoes exert the same effort paddling and hence maintain the same speed relative to the water. One pa
Serga [27]

Answer:

Speed of river is 0.45 m/s

Speed of boat is 2.65 m/s

Explanation:

v_r = Speed of river

v_c = Speed of canoe

v_r+v_c=2.8\ m/s

v_r-v_c=-1.9\ m/s

Adding the equations we get

2v_r=0.9\\\Rightarrow v_r=\frac{0.9}{2}\\\Rightarrow v_r=0.45\ m/s

0.42+v_c=2.8\ m/s\\\Rightarrow v_c=2.8-0.45\\\Rightarrow v_c=2.65\ m/s

Speed of river is 0.45 m/s

Speed of boat is 2.65 m/s

6 0
3 years ago
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