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OverLord2011 [107]

2 years ago

9

A less common type of radioactive particle emitted is the positron. If potassium-38 forms argon-38 by positron emission, the num

ber of a positron is and the charge is

1 answer:

aleksandr82 [10.1K]2 years ago

4 0

Potassium goes to argon so that a proton in the K nucleus "vanishes" into a positron (positive electron ?) but keeps the same atomic mass at 38. ? I'd say that the number of the positron was 0, and the charge was +1 electronic charge.

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A child slides down a hill on a toboggan with an acceleration of 1.8 m/s^2. If she starts at rest, how far has she traveled in :

DENIUS [597]

Explanation:

It is given that,

The acceleration of the toboggan, $a=1.8\ m/s^2$

Initial speed of the toboggan, u = 0

We need to find the distance covered by the toboggan. Using the second equation of motion as :

$s=ut+\dfrac{1}{2}at^2$

At t = 1 s

$s=\dfrac{1}{2}\times 1.8\times 1^2$

$s_1=0.9\ m$

At t = 2 s

$s=\dfrac{1}{2}\times 1.8\times 2^2$

$s_2=3.6\ m$

At t = 3 s

$s=\dfrac{1}{2}\times 1.8\times 3^2$

$s_3=8.1\ m$

Hence, this is the required solution.

4 0

3 years ago

Match the lithification processes.

Varvara68 [4.7K]

Answer:

ReCrystallization

Contact pressure causing grains to "grow" together.

It's a metamorphic process used to rearrange the atoms of the minerals in order to modify them in to the required form under the specific temperature and pressure. For example conversion of limestone into marble.

<em>Cementation:</em>

Precipitation of bonding agents between grains.

Cementation is the process in which the minerals in the form of fluid fills in spaces between the grains and binds them together upon crystallizing.

<em>Compaction:</em>

Increase in density due to weight of overburden.

Compaction as it's name indicate is the compaction of the sediments due to the heavy weight of the rocks which reduce their size and increase their density.

5 0

2 years ago

A concave mirror with a radius of curvature of 20 cm has a focal length of

xxTIMURxx [149]

Answer:

A concave mirror has a radius of curvature of 20 cm. What is it's focal length? If an object is placed 15 cm in front of it, where would the image be formed? What is it's magnification?

The focal length is of 10 cm, object distance is 30 cm and magnification is -2.

Explanation:

Given:

A concave mirror:

Radius of curvature of the mirror, as C = 20 cm

Object distance in-front of the mirror = 15 cm

a.

Focal length:

Focal length is half of the radius of curvature.

Focal length of the mirror = $\frac{C}{2}$ = 10 cm

According to the sign convention we will put the mirror on (0,0) point, of the Cartesian coordinate open towards the negative x-axis.

Object and the focal length are also on the negative x-axis where focal length and image distance will be negative numerically.

b.

We have to find the object distance:

Formula to be use:

⇒ $\frac{1}{focal\ length}= \frac{1}{image\ distance} + \frac{1}{object\ distance}$

⇒ Plugging the values.

⇒ $\frac{1}{-10} =\frac{1}{image\ distance}+\frac{1}{-15}$

⇒ $\frac{1}{-10} -\frac{1}{-15}=\frac{1}{image\ distance}$

⇒ $\frac{1}{-10} + \frac{1}{15}=\frac{1}{image\ distance}$

⇒ $\frac{-3+2}{30} =\frac{1}{image\ distance}$

⇒ $\frac{-1}{30} =\frac{1}{image\ distance}$

⇒ $-30\ cm=image\ distance$

Image will be formed towards negative x-axis 30 cm away from the pole.

c.

Magnification (m) is the negative ratio of mage distance and object distance:

⇒ $m=-\frac{image\ distance}{object\ distance}$

⇒ $m=-\frac{(-30)}{(-15)}$

⇒ $m=-2$

The focal length of the concave mirror, is of 10 cm, object distance is 30 cm and magnification is -2.

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3 years ago

A person travels by car from one city to an-

Mademuasel [1]

<h2>Answer:</h2>

<h2>Explanation:</h2>

First, let's refer to the distance formula:

$d=v*t$ , where d is distance, v is velocity or speed and t is time.

Now, let's find the distance covered by each individual speed that the car had:

<h3>1. Speed 1.</h3>

In order to use the formula, we need to convert minutes into hours since the speed is given in km/h.

21.1 min/60= 0.35 h.

Now, apply the distance formula.

d=(0.35h)*(86.8km/h)= 30.38 km.

<h3>2. Speed 2.</h3>

Convert minutes to hours again and do the same calculations.

10.6min/60=0.18h

d=(0.18h)*(106km/h)= 19.08 km.

<h3>3. Speed 3.</h3>

36.5min/60= 0.61h

d=(0.61h)*(30.9km/h)= 18.85 km.

<h3>4. Obtain the total distance.</h3>

The total distance must be given by the addition of all individual distances traveled by the car on each speed:

Total distance= 30.38 km + 19.08 km + 18.85 km= 68.31 km.

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1 year ago

What is the minimum force required to life a 50-N load with one fixed pulley?'

IRINA_888 [86]

One fixed pulley doesn't change the strength of the force that
pulls on the rope. The pulley only changes its direction. So,
to lift a 50-N load, you need to pull on the rope with at least 50-N .

8 0

2 years ago