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3 years ago

How many neutrons does element x have if it’s atomic number is 40 and it’s mass number is 82?

1 answer:

4 0

The atomic number gives you the number of protons element x has. Since the mass of protons and neutrons are almost similar(around 1 amu), the mass number can be thought of as the sum of protons and neutrons. so if element x whose atomic number is 40 has a mass number of 82, then we know that 42 of those must be neutrons.

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A physics student throws a softball straight up into the air. The ball was in the air for a total of 3.56 s before it was caught

meriva

Answer:

The initial velocity of the softball is 14.711 meters per second.

Explanation:

This is a case of an object which experiments a free fall, that is, an uniform accelerated motion due to gravity and in which effects from air friction and Earth's rotation can be neglected.

From statement we must understand that the student threw the softball upwards and it is caught at original position 3.56 seconds later. Initial and final heights, time and gravitational acceleration are known and initial speed is unknown. The following equation of motion is used:

$y = y_{o} + v_{o}\cdot t + \frac{1}{2}\cdot g \cdot t^{2}$ (Eq. 1)

Where:

$y_{o}$ - Initial height of the softball, measured in meters.

$y$ - Final height of the softball, measured in meters.

$v_{o}$ - Initial velocity of the softball, measured in meters per second.

$t$ - Time, measured in seconds.

$g$ - Gravitational acceleration, measured in meters per square second.

If we know that $y = y_{o}$ , $t = 3.56\,s$ and $g = -9.807\,\frac{m}{s^{2}}$ , the initial velocity of the softball is:

$v_{o}\cdot (3\,s)+\frac{1}{2}\cdot (-9.807\,\frac{m}{s^{2}} )\cdot (3\,s)^{2} = 0$

$3\cdot v_{o} -44.132\,m= 0$

$v_{o} = 14.711\,\frac{m}{s}$

The initial velocity of the softball is 14.711 meters per second.

8 0

3 years ago

Unlike acceleration and velocity, speed does not need to specify

frosja888 [35]

Unlike acceleration and velocity, speed does not need to specify the direction of motion. Speed is a scalar quality.

4 0

3 years ago

Acceleration is generally defined as the time rate of change of velocity. When can it be defined as the time rate of change of s

Lena [83]

Answer:

When the velocity doesn't change its direction

Explanation:

Since velocity vector has 2 components: direction and magnitude, and speed is the velocity's magnitude. So if the velocity doesn't change its direction, we essentially use its magnitude, aka speed, to calculate the rate of change for acceleration.

8 0

3 years ago

Read 2 more answers

An assumption central to all scientific inquiry is causality, which means that

zavuch27 [327]

<h2>Answer</h2>

Causality means reason behind the process

<h2>Explanation</h2>

In the scientific inquiries, scientists perform different activities with the help of previous knowledge and scientific ways to renew the knowledge or discover the new ideas. It is a common belief that in every process that is happening in nature have many functions and reasons behind it. Scientists are always in the struggle to find these reasons and their importance regarding their happenings. When the scientists are in hurry to know about the causality, it means they are helping the scientific knowledge with the discovery of new reasons for happens.

7 0

3 years ago

The potential difference between the plates of an air-filled parallel-plate capacitor with a plate separation of 4 cm is 51 V. W

Salsk061 [2.6K]

Answer:

Explanation:

Electric field between plates of a parallel plate capacitor is uniform .

In a uniform electric field , relation between electric field and potential gradient is as follows

electric field = potential gradient [ E = - dV / dl ]

in the given case ,

dV = 51 V ,

dl = 4 cm

= 4 x 10⁻² m

E = 51 / 4 x 10⁻²

= 12.75 x 10² V / m

= 1275 V / m

6 0

3 years ago