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Naddika [18.5K]
3 years ago
9

Alkali metals are extremely reactive because they a. have very small atomic masses. b. are not solids at room temperature.

Physics
1 answer:
irinina [24]3 years ago
5 0

Answer:

a.

Explanation:

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Consider an elevator with a table and a book on top of the table. The mass of the table is 10kg and the mass of the book is 2kg.
Step2247 [10]

Newton's second law allows us to find the force of the block on the table is 126 N

Newton's second law says that the net force is proportional to the product of the mass and the acceleration of the body

                Σ F = m a

Where the bold letters indicate vectors, m is the mass and the acceleration of the body

A free body diagram is a diagram where the forces are represented without the details of the bodies, in the attached we can see a free body diagram of the system.

Let's start by finding the acceleration of the elevator with kinematics  

                 v = v₀ + a t

                 a = \frac{v-v_o}{a}  

Where v and v₀ are the current and initial velocity, respectively, at acceleration and t is the time

                 a = \frac{8-1}{2}

                 a = 3.5 m / s²

Let's write Newton's second law for each body

The book

                N₂ - W₂ + N₁ = m a

               

Table

                N₁ - W₁ - W₂ = M a

                W₁ = Mg

                W₂ = mg

                N₁ = (M + m) g + M a

                N₁ = (10 + 2) 9.8 + 10 3.5

                N₁ = 152.6 N

This is the reaction of the earth to the support of the block and the table

               N₂ = ma + m g  - N₁

               N₂ = m ( a +g) - N₁  

               N₂ = 2 (3.5 + 9.8) - 152.6

               N₂ = 26.6 - 152.6

               N₂ = -126 N

The negative sign indicates that the direction is opposite to the one assigned, this is the action of the block on the table.

In conclusion using Newton's second law we can find the forces of the block on the table is 126 N

Learn more here: brainly.com/question/19860811

4 0
3 years ago
The amount of energy necessary to remove an electron from an atom is a quantity called the ionization energy, Ei. This energy ca
Verizon [17]

Answer:

The value is E_i  =  1.5596 *10^{-18} \  J

Explanation:

From the question we are told that

The wavelength is \lambda  =  48.2 nm  =  48.2  *10^{- 9 }\  m

The velocity is v = 2.371*10^6 \ m/s

The mass of electron is m_e  =  9.109*10^{-31} \  kg

Generally the energy of the incident light is mathematically represented as

E =  \frac{h *  c}{\lambda}

Here c is the speed of light with value c =  3.0 *10^{8} \  m/s

h is the Planck constant with value h = 6.62607015 *  10^{-34 }  J\cdot s

So

E =  \frac{6.62607015 *  10^{-34 }* 3.0 *10^{8}}{48.2  *10^{- 9 }}

=> E = 4.12 *10^{-18} \  J

Generally the kinetic energy is mathematically represented as

E_k  =  \frac{1}{2} *  m_e * v^2

=> E_k  =  \frac{1}{2} *  9.109*10^{-31} * (2.371*10^6 )^2

=> E_k  =  2.56 *0^{-18} \  J

Generally the ionization energy is mathematically represented as

E_i  =  4.12 *10^{-18} -   2.56 *0^{-18}

=>     E_i  =  1.5596 *10^{-18} \  J

7 0
3 years ago
The angle of incidence and the angle of reflection are measured from the_____, the perpendicular to the surface.
kogti [31]

I believe it is angles

6 0
3 years ago
A skateboarder with a mass of 67.0 kilograms (including the skateboard) rolls down from the top of a ramp, reaching a velocity o
Llana [10]

The potential energy of the skateboarder at the top of the ramp is

489.1 J.

<h3>Is kinetic energy always equal to potential energy?</h3>

The amount of kinetic energy change and the amount of potential energy change are equal in all physical processes that take place in closed systems. When the kinetic energy rises, the potential energy falls, and vice versa.

Potential energy is the stored energy in any object or system as a result of its position or component arrangement. However, external factors like air or height have no effect on it. The energy of a moving object or system is referred to as kinetic energy.

Potential energy = kinetic energy

Potential energy = 1/2mv²

Potential energy = 1/2 × 67×7.3

Potential energy = 489.1 J.

To know more about kinetic energy visit:

brainly.com/question/26472013

#SPJ1

5 0
1 year ago
Electromagnetic waves are ________ waves.
n200080 [17]
D. Transverse waves
3 0
3 years ago
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