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3 years ago

Describe a sea-level transgression

1 answer:

7 0

<span>Some geographic areas endure cycles between these two processes called transgressive-regressive sequences. The rocks of western Pennsylvania are one example. Sandy beaches often leave observable records of transgression by covering marsh sediments that were once behind it as it moves inland. The original sediments are then covered by even deeper water sediments, which geologists can trace and record. It is generally believed that transgression will increase in accordance with rising sea levels worldwide</span>

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What are the three types of motion

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Rectilinear Motion, Circular Motion and Periodic Motion.

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3 years ago

Which statement would be true about a water molecule if it has a linear shape

mihalych1998 [28]

It would be easily bond with other water molecules.

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3 years ago

A 15kg dog jumps out of a 40kg canoe. If the dogs velocity is 1.2m/s, what is the velocity of the canoe?

vivado [14]

Answer:

v = -0.45 m/s

Explanation:

Assuming the canoe was initially at rest with momentum L = 0

and that the dog's velocity is in the positive direction

conservation of momentum

0 = 15(1.2) + 40v

v = -0.45 m/s

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3 years ago

A marathon runner completes a 42.238 km course in 2 h, 31 min, and 46 s . There is an uncertainty of 29 m in the distance run an

icang [17]

Answer:

The percentage uncertainty in the average speed is 0.10% (2 sig. fig.)

Explanation:

Consider the formula for average speed $\bar{v}$ .

$\displaystyle \bar{v} = \frac{s}{t}$ ,

where

$s$ is the total distance, and
$t$ is the time taken.

The percentage uncertainty of a fraction is the sum of percentage uncertainties in

the numerator, and
the denominator.

What are the percentage uncertainties in $s$ and $t$ in this question?

The unit of the absolute uncertainty in $s$ is meters. Thus, convert the unit of $s$ to meters:

$s = \rm 42.238\;km = 42.238\times 10^{3}\;m$ .

$\begin{aligned}\displaystyle \text{Percentage Uncertainty in }s &= \frac{\text{Absolute Uncertainty in } s}{\text{Measured Value of }s}\times 100\% \\ &=\rm\frac{29\; m}{42.238\times 10^{3}\;m}\times 100\%\\ &= 0.0687\%\end{aligned}$ .

The unit of the absolute uncertainty in $t$ is seconds. Convert the unit of $t$ to seconds:

$t = \rm 2\times 3600 + 31\times 60 + 46 = 9106\;s$

Similarly,

$\begin{aligned}\displaystyle \rm \text{Percentage Uncertainty in }t &= \frac{\text{Absolute Uncertainty in }t}{\text{Measured Value of }t}\times 100\% \\ &=\rm\frac{46\; s}{9106\;s}\times 100\%\\ &= 0.0329\%\end{aligned}$ .

The average speed $\bar{v}$ here is a fraction of $s$ and $t$ . Both $s$ and $t$ come with uncertainty. The percentage uncertainty in $\bar{v}$ will be the sum of percentage uncertainties in $s$ and $t$ . That is:

$\text{Percentage Uncertainty in }\bar{v}\\=(\text{Percentage Uncertainty in } s) + (\text{Percentage Uncertainty in } t)\\ = 0.0687\% + 0.0329\%\\ = 0.010\%$ .

Generally, keep

two significant figures for percentage uncertainties that are less than 2%, and
one for those that are greater than 2%.

The percentage uncertainty in $\bar{v}$ here is less than 2%. Thus, keep two significant figures. However, keep more significant figures than that in calculations to make sure that the final result is accurate.

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4 years ago

After a long night of cramming for a test, your college roommate hits his head forcefully against the wall of your room in despa

sweet [91]

Answer:

See the answer below

Explanation:

Newton's third law states that for every action, there will always be an opposing reaction of equal magnitude to the action.

<em>Hence, the wall will exert an equal opposing force to the head and the roommate will feel this opposing force as pains and/or headache. </em>

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3 years ago