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3 years ago

The early earth was much cooler than it is today. a. True b. False

1 answer:

Pie3 years ago

5 0

This statement is true. Early earth was much cooler than it is today.

This is because the pollution as well as the population number was very small compared to nowadays population and pollution.
The pollution mainly is causing a decay in the ozone layer which protects the earth from uv rays. Thus, more of these rays enter the atmosphere and increase the temperature.
The increase in population along with the decrease in green areas leads to the increase in the percentage of carbon dioxide in the atmosphere, which again leads to an increase in the temperature.

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Un resorte se monta horizontalmente con su extremo izquierdo fijo. Conectando una balanza de

zavuch27 [327]

Translation of important question part (Google translation used)

Force of 6N causes a displacement of 0.03m. remove the balance and connect a body 0.5 kg to the end, pull it to move it 0.02 m, release it and see how it oscillates.

(a)Determine the spring constant.

(b)Calculate angular velocity, frequency, and oscillation period

Answer:

(a)K=200 N/m

(b) w= 20 rad/s f=3.2 Hz T=0.3125 s

Explanation:

(a)

From Hooke's law, we deduce that F=kx where F is applied force, k is spring constant and x is extension of the spring. Making k the subject of the formula then k=F/x and substituting F with 6 N and x with 0.03 m then k=6/0.03=200 N/m

(b)

Angular velocity, w is given by $w= \sqrt{\frac {k}{m}}$ where m is the mass and k is spring constant calculated in part a above. Substituting mass with 0.5 kg and k with 200 N/m then

$w= \sqrt{\frac {200}{0.5}}=20 rad/s$

We know that frequency, f is given by $f=\frac {w}{2\pi}$ and substituting 20 rad/s for w then

$f=\frac {20}{2\pi}=3.1830988618379067153776752674502872406891\approx 3.2 Hz$

Finally, oscillation period, T is usually the reciprocal of frequency hence T=1/f and substituting f with 3.2 Hz then T=1/3.2=0.3125 s

7 0

3 years ago

12. An example of an atom that has no charge is one that has A. 3 protons, 1 electron, and 3 neutrons. B. 3 protons, 2 electrons

andreyandreev [35.5K]

_____________________________

[D. 2 protons, 2 electrons, and 1 neutron.]

As we know that, protons are embedded in the nucleus with neutron having no charge. So, nucleus has positive charge. Electrons are revolved around the nucleus of the atom. Proton has positive charge and electron has negative charge.

Number of proton = Number of electron.

Hence, both 2 protons and 2 electrons make the atom electrically neutral. So, the net charge of atom is 0. Neutron are the subatomic particle which has only mass.

_____________________________

8 0

3 years ago

Write four (4) strategies on how can we manage land use around South Florida. For each strategy, explain it's benefits to the en

a_sh-v [17]

Answer:

What are some ways we can improve on our land use?

- Avoid deforestation and close the forest frontier.

The first-order priority is to end deforestation by closing the "forest frontier" or intact forests, to development.

- Increase agricultural productivity.

- Restore forests and landscapes.

- Reduce food loss and waste.

- Improve diets

3 0

3 years ago

Any form of stored energy is described as

seropon [69]

Potential energy , hope this helps :)

4 0

2 years ago

a railroad tie weights 920 N and is 2.6 m long. How much force is required to: pick it up off the ground? lift one end and rotat

lukranit [14]

1) The minimum force needed is 920 N

2) The minimum force is 460 N

3) The minimum force is 598 N

Explanation:

We can answer this part by simply looking at the forces involved. In fact, there are two forces acting on the railroad:

Its weight, W, acting downward
The force applied to lift it, F, upward

So the net force on the railroad is

$\sum F = F - W$

where

W = 920 N is the weight of the railroad

In order to lift the railroad, the net force must be upward, so

$\sum F \geq 0$

And therefore

$F\geq W$

which means that the minimum force needed is equal to the weight of the railroad, 920 N.

In this case, we have to use the principle of equilibrium of moments.

In fact, when the railroad rotates uniformly (=constant angular speed) about its end, it means that the moment produced by the weight (acting in one direction) is equal to the moment produced by the force applied (acting in the other direction). Therefore, we can write:

$W \frac{L}{2} = F L$

where

W = 920 N is the weight

L = 2.6 m is the length of the railroad

F is the force applied

We wrote L/2 on the left of the equation because the weight acts at the center of mass of the railroad (located at the midpoint), while on the right it is L because the force F is applied at the end of the railroad.

Solving for F,

$F=\frac{W}{2}=\frac{920}{2}=460 N$

This problem is similar to the previous part, however in this case, the force applied F is applied 0.6 m from the end, pivoting around the opposite end.

This means that the distance between the point of application of the force F and the pivot is

L' = L - 0.6

where

L = 2.6 m

Therefore the equation for the equilibrium of moments becomes

$W\frac{L}{2}=F(L-0.6)$