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3 years ago

If the atomic number of an atom is 4 and the mass number is 9, then how many electrons does it have

1 answer:

5 0

The atomic number of an atom says how many protons it has. This number cant change, since the atomic number is what gives elements their identities (in the periodic table, at least).
The mass number, on the other hand, says how many protons AND neutrons the atom has (so, the sum of P+ and N0). So, electrons have nothing to do with this number.
Atoms are neutrally charged, which means there has to be an equal number of positive and negative particles. The negative particles of an atom are its electrons, and since our atom has 4 protons, it must also have 4 electrons.

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answers At the beginning of 2019, Robotics Inc. acquired a manufacturing facility for $12.3 million. $9.3 million of the purchas

pshichka [43]

Answer:

$613,077

Explanation:

Calculation for the depreciation on the building for 2021

First step is to calculate the depreciation expense for the year 2019 and 2020 using this formula

Depreciation expense = (Purchase price - Residual value) ÷ (Useful life)

Let plug in the formula

Depreciation expense= ($9,300,000 - $1,300,000) ÷ (20 years)

Depreciation expense= ($8,000,000) ÷ (20 years)

Depreciation expense= $400,000

Second step is to calculate the book value for the year 2021 using this formula

Book value = Purchase price - Depreciation expenses *2 years

Let plug in the formula

Book value= $9,300,000 - $400,000 × 2

Book value= $8,500,000

Last step is to calculate the depreciation for 2021 using this formula

2021 Depreciation=(Book value-Residual value)÷Useful life

2021 Depreciation= ($8,500,000 - $530,000) ÷ (15 years - 2 years)

2021 Depreciation=$7,970,000÷13 years

2021 Depreciation= $613,077

Therefore the depreciation on the building for 2021 will be $613,077

8 0

3 years ago

If the soccer ball has a mass of 284g, and gravitational force is 9.81 m/s2 on Earth, what is the weight of the soccer ball?

bagirrra123 [75]

Answer:

2.79 N
8.34 N
Watermelon

Explanation:

Weight of soccer ball

Weight = mass (in kg) × gravitational force
Weight = 284 x 10⁻³ x 9.81
Weight = 0.284 x 9.81
Weight = 2.79 N (approximately)

Weight of watermelon

Weight = mass (in kg) x gravitational force
Weight = 850 x 10⁻³ x 9.81
Weight = 0.85 x 9.81
Weight = 8.34 N (approximately)

As the watermelon has more weight, it will hit the ground first.

4 0

2 years ago

Where does the energy come from in a nuclear fission reaction?

poizon [28]

Answer:ni

Explanation:

nnn

4 0

3 years ago

A 55.0-kg lead ball is dropped from the Leaning Tower of Pisa. The tower is 55.0 m high. What is the speed of the ball after it

PolarNik [594]

Answer:

The speed of the ball is 9.07 m/s.

Explanation:

Given that,

Mass of the lead ball, m = 55 kg

Height of the tower, h = 55 m

We need to find the speed of the ball it has traveled 4.20 m downward, x = 4.2 meters

The initial speed of the ball will be 0 as it was at rest initially. Let v is the speed of the ball after it has traveled 4.20 m downward. It is a case of equation of motion such that :

$v^2-u^2=2ax$