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2 years ago

Describe three physical changes that occur in nature?

2 answers:

8 0

Answer: Physical changes in nature could then be erosion in a mountain, the melting of snow, and a river freezing over from the cold. Since none of these changes affect the chemical composition of the mountain, the snow, or the river, they are physical changes.

Explanation:

Snezhnost [94]2 years ago

8 0

Answer:rain, melting of ice, eating of grass

Explanation:

Those call all go back to how they were before without using chemicals

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A 45.0-kg girl is standing on a 168-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat,

muminat

Answer:

The speed of the plank relative to the ice is:

$v_{p}=-0.33\: m/s$

Explanation:

Here we can use momentum conservation. Do not forget it is relative to the ice.

$m_{g}v_{g}+m_{p}v_{p}=0$ (1)

Where:

m(g) is the mass of the girl
m(p) is the mass of the plank
v(g) is the speed of the girl
v(p) is the speed of the plank

Now, as we have relative velocities, we have:

$v_{g/b}=v_{g}-v_{p}=1.55 \: m/s$ (2)

v(g/b) is the speed of the girl relative to the plank

Solving the system of equations (1) and (2)

$45v_{g}+168v_{p}=0$

$v_{g}-v_{p}=1.55$

$v_{p}=-0.33\: m/s$

I hope it helps you!

8 0

2 years ago

When working with a powered instrument, the swirling effect produced by the water stream within the confined space of a periodon

Lina20 [59]

Answer:

Acoustic microstreaming

Explanation:

Acoustic microstreaming is the swirling effect produced by water stream confined in a spaced of a periodontal pocket.

It is the movement of water in a particular direction as a result of mechanical pressure within the fluid body.
They are often used in dental procedures to remove particulates from the teeth.
It mostly relies on the properties of sound waves to achieve this goal

3 0

2 years ago

Which of the following safety devices provides a weak link in a circuit that will melt if it received too much current, thus bre

SVETLANKA909090 [29]

The correct answer is B. Fuse.

Fuses were commonly used in houses up to recent ages, when circuit breakers became the more popular options, as they don't have to be changed every time they melt, since they don't melt.

4 0

2 years ago

Read 2 more answers

An electron is a negatively charged particle that has a charge of magnitude, e - 1.60 x 10-19 C. Which one of the following stat

Ivahew [28]

Answer:

The electric field is directed toward the electron and has a magnitude of $E=\frac{ke}{r^{2} }$ .

Explanation:

An electric field is define as the surrounding of charges which exert a force on each other and this force can be attractive or repulsive depends on the charge.

In the given case electron is given and the magnitude of charge on electron is $e=1.6\times 10^{-19}C$

Electric field can be represented as,

$E=\frac{kQ}{r^{2} }$

Here, r is the distance between the point ande charge, k is the electric field constant and Q is the charge.

In the given question an electron is given so electric field will be,

$E=\frac{ke}{r^{2} }$

As we know that electric field start from the positive charge and vanish in the negative charge.

So, here the electric field will be $E=\frac{ke}{r^{2} }$ and it is directed toward the electron because of negative charge on the electron.

6 0

2 years ago

A bicyclist is traveling at +25m/s when he begins to decelerate at -4m/s2. How fast is he traveling after 5 seconds

kotegsom [21]

Answer:

+5m/s

Explanation:

When doing the math we figure out that e is going to be slowing down at -4m/s² for 5 seconds. In total he is slowing down -20m/s which we take from the total speed of +25m/s to get his current new speed.

7 0

2 years ago