A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force on her hand is.

You wish to start a fire by reflecting sunlight from a mirror onto some paper under a pile of wood which means the best choice of the type of mirror for this operation is a concave one and is denoted as option B.

This type of mirror usually has a reflective surface that is curved inward and away from the light source. They also reflect light inward to one focal point which is done by reflecting all the rays parallel to its axis and converge them at a single point.

For fire to occur, then we need a large concentration of light rays which will help reflect all the sunlight from a mirror onto some paper under a pile of wood thereby causing the fire.

This is therefore the reason why concave mirror was chosen as the most appropriate choice.

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According to Gauss law,  the electric flux is defined as the electric field multiplied by the area of the surface in a plane perpendicular to the field.

Gauss law is defined mathematically in Equation 1

Φ=Q ϵo               (1)

Where;

Q is enclosed charge

ϵo is the permittivity of the free space

According to the above gaussian relation, If the charge is doubled, then flux will also be doubled. This is because there is a direct relationship between the total flux and charge present in the electric field. This means that the net electric flux is dependent on the charge moving through the surface of the cube.

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The magnitude of the acceleration of the robot is 1m/s^2 .

Given ,

A toy doll and a toy robot are standing on a frictionless surface facing each other .

The mass of the doll = 0.20kg

The mass of the robot = 0.30kg

Force applied by the robot on the doll = 0.30N

We know the force and mass of the robot , so from this we can calculate the acceleration by applying Newton's laws of motion ,

Thus , F= ma

a = F/m = 0.30N / 0.30k

a = 1 m/s^2

Hence , the magnitude of the acceleration of the robot is 1m/s^2 .

Acceleration is the rate of change in velocity.

Positive acceleration it occurs when an object speeds up. Negative acceleration it occurs when an object slows down.

Acceleration is a change of velocity over a period of time, expressed by the equation,

A=Δv/t

The unit of acceleration is m/s^2.

The dimensional formula of acceleration is [M^0 L^1 T^-2] .

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Answer:

1) Constants are variables that are kept the same throughout an experiment.

2) An independent variable is a variable that is manipulated by the experimenter.

3) A dependent variable is a variable that is measured by the experimenter.

Explanation:

Answer:

Element of a compound typically cannot be separated by physical means because atoms are chemically bonded together

Explanation:

Compounds are substances composed of two or more elements chemically combined that can be separated into simpler substances only by chemical means

Gravity is the non contact force.

Gravity is a fundamental interaction in physics that causes all objects with mass or energy to attract one another. The electromagnetic force, the weak interaction, and the strong interaction are all significantly stronger than gravity, which is by far the weakest of the four fundamental interactions. As a result, it has no appreciable impact on subatomic particle level phenomena. However, at the macroscopic level, gravity is the most important interaction between things and governs the motion of planets, stars, galaxies, and even light.

On Earth, gravitational pull lends weight to tangible objects, and the moon's gravitational pull generates ocean tides. In addition, gravity plays a significant role in many biological processes, including gravitropism, which directs plant growth, and the movement of fluids in multicellular organisms. Gravity may affect how the immune system and cells differentiate in the human body, according to research on the effects of weightlessness.

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About 1.3 seconds the light takes to reach from the moon to the earth.

We know that the closest object to our earth is the Moon. Its distance from the earth is about 240,000 miles, so light from the Moon takes 1 and 1/3 seconds to get from the Moon to Earth while on the other hand, sun is  almost 400 times farther from earth as compared to the moon so the light reaches from sun is about 8 minutes 30 seconds.

So we can conclude that about 1.3 seconds the light takes to reach from the moon to the earth.

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Excess charge on an isolated conductor must reside on its surface because excess charge moves away until they reach the surface of the body.

Charged conductors in electrostatic equilibrium exhibit a number of interesting properties. The electric field beneath the surface of a charged conductor is zero when it is in electrostatic equilibrium, which is one of its properties. The repulsive nature of force between similar charges and the liberty of motion of charges within a conductor allows for the establishment of equilibrium within charges present in the conductor. Due to this fact, excess charges carry like type of charge as contained within the conductor they are thus repelled away from the conductor till they reach the outer surface of the conductor.

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V or total voltage is 6 volts because when multiple power supplies of the same voltage are connected in parallel, the applied voltage is same and the current equally divides between the number of power sources.

Divide I(t) or total current 0.25 amps between the two power sources.

Is=I(t)/Ns

Is=0.25amps/2sources

Is=.125amps

Voltage is the difference in electrical potential between two points.

Current is just the rate of flow of electric charge.

Each power source supplies .125amps of current to the load

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The charge per unit length on the outer surface is [tex]3\lambda[/tex]

Charge per unit length of the wire [tex]= {\lambda}[/tex].

Charge per unit length of the cylinder =[tex]{2\lambda}[/tex]

Gauss's law is a principle that connects the distribution of electric charge to the resulting electric field. In its integral form, it asserts that the flux of the electric field out of any closed surface, regardless of how that charge is distributed, is proportional to the electric charge enclosed by the surface.

The total charge per unit length of the cylinder is equal to the charge per unit length of the inner part of the cylinder plus the charge per unit length of the outer part:

Solve for [tex]{\lambda_{\text{out}}}[/tex] :

[tex]\lambda_{\text{out}}=2\lambda-\lambda_{\text{in}}[/tex]

Substitute for [tex]{\lambda_{\text{in}}}[/tex] :

[tex]\lambda_{\text{out}}&=2\lambda-(-\lambda)\\ &={3\lambda}}[/tex]

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The ball will leave the ground with the velocity of 4.5 m/s.

Velocity is the distance travelled in a specific direction per time taken. It is measured in m/s

Given that a tennis ball is dropped from 1.98 m above the ground. It rebounds to a height of 1.05 m. The acceleration of gravity is 9.8 m/s².

Using the formula

v² = u² - 2gH

0 = u² - 2 × 9.8 × 1.05

u² = 20.58

u = √20.58

u = 4.54 m/s

Therefore, the ball will leave the ground with the velocity of 4.5 m/s.

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According to the question a plastic rod that has been charged to − 15nc touches a metal sphere. Afterward, the rod's charge is − 1.0nc.The electrons will be transferred from the plastic rod to the metal sphere and the number of electrons ( n ) = 8.73 * 10^10

First of all, write the initial charge on the plastic rod, and then it touches the metallic sphere. Then, a few amounts of charge are transferred to the steel sphere. Later, calculating the price difference between the plastic rod and metal sphere, the kind of charged particle transferred may be decided. Ultimately, the number of electrons may be calculated by the use of the overall charge and the rate of the electron.

The expression of the total charge in electrostatics is Q = ne

Q = charge

n = number of electrons

e = charge of the electron

The initial charge on the plastic rod ( Qplastic ) = -15nC

Final charge on the metal sphere after it was touched by the plastic rod ( Qmetal ) = -1nC

The charge transferred from the metal rod to the sphere = ( Q = Qplastic -   Qmetal )

Therefore Q = - 15nC - ( -1nC )

Q = -14nC

The plastic rod is negatively charged, so the electrons will be transferred to the metal sphere. The electrons will be transferred from the plastic rod to the metal sphere.

The expression of the total charge in electrostatics is Q = ne

The expression for n = Q / e

Q = -14nC

The charge on 1 electron = 1.602 * 10^-19 C.

Number of electrons ( n ) = -14nC ( 10^-9C/1nC ) / -1.602 * 10^-19 C.

Number of electrons ( n ) = 8.73 * 10^10

Threfore the number of electrons ( n ) = 8.73 * 10^10

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The density of the earth is 3.51×10¹⁰ kg/m³

Density can be defined as the ratio of mass to the volume of a body. The S.I unit of density is kg/m³

To calculate the density of the earth, we use the formula below.

Formula:

Where:

From the question,

Given:

Note: Since the earth is a spherical in shape, we can calculate the volume of the earth using the volume of a sphere

Substitute these values into equation 1

Hence, the density of the earth is 3.51×10¹⁰ kg/m³.

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The minimum spacing the engineer should leave between the sections to eliminate buckling is 0.011 m.

To calculate the minimum space the engineer must leave in other to eliminate bulking, we use the coefficient of linear expansivity of steel.

This can be defined as the increase in length, per unit length, per degree rise in temperature.

To calculate the minimum space, we use the fomula below

Formula:

Make L₂ the subject of the equation

From the question,

Given:

Substitute these values into equation 2

Hence, the minimum spacing the engineer should leave between the sections to eliminate buckling is 0.011 m.

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The forces acting on the baseball are air resistance, and force of gravity.

The forces which act on an object moving upward will either oppose the motion of the object or help to speed up the object.

The forces present during upward motion include;

The forces acting on a baseball thrown upwards which also travels rightward include the following;

Thus, the forces acting on the baseball are air resistance, and force of gravity.

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The complete question is below:

Consider this situation: A baseball travels upward and

rightward through the air. Of the forces listed, identify which

act upon the baseball. (force of air resistance, force of gravity, weight of the ball, frictional force).

answer:

Use this equation (v=Δx/t); plug in velocity (0.500 m/s) and the time (2.4 s), then solve for displacement… (Δx=1.2 m)

If a coin is rolled in a straight line along a balcony edge at a steady speed of 0.46 m / s , then the distance traveled by this coin in 2.4 seconds would be 1.104 meters.

There are three equations of motion given by Newton,

v = u + at

S = ut + 1/2×a×t²

v² - u² = 2×a×s

As given in the problem If a coin is rolled in a straight line along a balcony edge at a steady speed of 0.46 m / s ,

The distance traveled by the coin = 0.46 × 2.4

                                                         =1.104 meters per second

For another coin , by using the first equation of motion ,

v = u + a × t

78.8 = 0 + a × 8.0

a = 78.8 / 8.0

a = 9.85 m / s²

Thus,  the distance traveled by this coin in 2.4 seconds would be 1.104 meters .

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The force required to accelerate the block is 28 N.

The acceleration of a cart with a mass of 25 kg and applied force of 50 N is 2 m/s².

The mass of a block of ice that is accelerated to 6 m/s2 by a force of 3 Newtons is 0.5kg.

A free body diagram is a sketch of forces acting on an object. It consists of the applied force, weight of the object, frictional force and normal reaction.

The force required to accelerate the block is calculated as follows;

F = ma

F = 3.5 kg x 8 m/s²

F = 28 N

The acceleration of a cart with a mass of 25 kg and applied force of 50 N is calculated as follows;

a = F/m

a = 50/25

a = 2 m/s²

The mass of a block of ice that is accelerated to 6 m/s2 by a force of 3 Newtons is calculated as follows;

m = F/a

m = 3 N / 6 m/s²

m = 0.5 kg

A free body diagram is a sketch of forces acting on an object. It consists of the applied force, weight of the object, frictional force and normal reaction.

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Mitochondria is a type of organelle in the athlete’s cells supplies the energy for cellular function.

Since mitochondria are the cellular organelles in charge of producing aerobic ATP, the "health" of mitochondria is crucial for proper cellular operation

Mitochondria. Dictionary Britannica, Inc. Mitochondria, or "powerhouses," are oval-shaped organelles that are present in the majority of eukaryotic cells. During cellular respiration, substances like glucose are converted by mitochondria into ATP, an energy molecule (adenosine triphosphate).

The generation of ROS by mitochondria can result in oxidative damage to mitochondrial proteins, membranes, and DNA, impairing their capacity to synthesize ATP and perform a wide range of metabolic processes, including the tricarboxylic acid cycle, fatty acid oxidation, the urea cycle, amino acid metabolism, haem synthesis, and FeS center assembly, which are crucial to the normal functioning of most cells. The tendency of mitochondria to release intermembrane space proteins, such as cytochrome c (cyt c), to the cytosol by mitochondrial outer membrane permeabilization (MOMP), and so trigger the cell's apoptotic machinery, can also be increased by mitochondrial oxidative damage. The mitochondrial permeability transition pore (PTP), which opens up the inner membrane to tiny molecules in conditions like ischaemial reperfusion damage, is also induced by mitochondrial ROS generation. So it should come as no surprise that mitochondrial oxidative damage plays a role in a variety of diseases. Additionally, mitochondrial ROS may behave as a modifiable redox signal, impacting a number of activities in the mitochondria, cytosol, and nucleus in a reversible manner.

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The mobility of the light source depends on the interaction between the magnetic and electric forces.

Cathode ray refers to the electron beam that moves from the negatively charged cathode to the positively charged anode at the other end of the vacuum tube.

J. J. Thomson demonstrated that the identical beam deflections produced tubes with cathodes composed of varied materials and containing a range of gases prior to evacuation.

This discovery is significant because the interaction of the magnetic and electric forces determines the mobility of the light source.

Therefore, the interaction of the magnetic and electric forces determines how mobile the light source is.

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Answer:

Explanation:

Traumatic brain injury (TBI) happens when a sudden, external, physical assault damages the brain. It is one of the most common causes of disability and death in adults. TBI is a broad term that describes a vast array of injuries that happen to the brain. The damage can be focal (confined to one area of the brain) or diffuse (happens in more than one area of the brain). The severity of a brain injury can range from a mild concussion to a severe injury that results in coma or even death.

Brain injury may happen in one of two ways:

CLOSE BRAIN INJURY : Closed brain injuries happen when there is a nonpenetrating injury to the brain with no break in the skull. A closed brain injury is caused by a rapid forward or backward movement and shaking of the brain inside the bony skull that results in bruising and tearing of brain tissue and blood vessels. Closed brain injuries are usually caused by car accidents, falls, and increasingly, in sports. Shaking a baby can also result in this type of injury (called shaken baby syndrome).

PENETRATING BRAIN INJURY: Penetrating, or open head injuries happen when there is a break in the skull, such as when a bullet pierces the brain.

DIFFUSE AXONAL INJURY: Is the shearing (tearing) of the brain's long connecting nerve fibers (axons) that happens when the brain is injured as it shifts and rotates inside the bony skull. DAI usually causes coma and injury to many different parts of the brain. The changes in the brain are often microscopic and may not be evident on computed tomography (CT scan) or magnetic resonance imaging (MRI) scans.

PRIMARY BRAIN INJURY: Refers to the sudden and profound injury to the brain that is considered to be more or less complete at the time of impact. This happens at the time of the car accident, gunshot wound, or fall.

SECONDARY BRAIN INJURY : Refers to the changes that evolve over a period of hours to days after the primary brain injury. It includes an entire series of steps or stages of cellular, chemical, tissue, or blood vessel changes in the brain that contribute to further destruction of brain tissue.

The entire battery should be charged, as a battery being tested has five cells testing normal and one cell showing very low, so option B is correct.

A battery is a component that turns chemical energy into electrical energy and stores it. This process is called electrochemistry, and the structure that supports a battery is referred to as an electrochemical cell. One or more electrochemical cells can be used to create a battery, as in Volta's original pile. Two electrodes and an electrolyte are the main components of an electrochemical cell.

Some popular batteries are only intended for one usage (known as primary or disposable batteries). The electrons only travel in one direction from the anode to the cathode. Either the buildup of reaction products on the electrodes prevents the reaction from continuing, or their electrodes get depleted as they release their positive or negative ions into the electrolyte, and it is finished. The battery is eventually disposed of (or, ideally, recycled; however, that is a whole different Nova topic).

Therefore, the entire battery should be charged, as a battery being tested has five cells testing normal and one cell showing very low.

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The volume occupied by the gas at 3.1 atm pressure will be 11.12 L.

When a gas is maintained at a constant temperature and with a certain mass, Boyle's law states that the pressure of the gas is inversely proportional to its volume.

To put it another way, as long as the temperature and volume of the gas remain constant, the pressure and volume of the gas are inversely proportional to one another. In 1662, the Anglo-Irish chemist Robert Boyle proposed the Boyle's law.

According to Boyle's law :

P1V1=P2V2 where,

P1 and P2 are the pressure and,

V1 and V2 are the volume of container.

As per the question, the given values are :

V1=15 L

P1= 2.3 atm and,

P2= 3.1 atm

So by using Boyle's theorem :

2.3 atm× 15 L = 3.1 atm× V2

34.5=3.1 atm × V2

V2=11.12 L

Hence, the volume at 3.1 atm pressure will be 11.12 L.

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The velocity of a baseball thrown across a field is (V)= 10m/s

Velocity of a particle is its speed and the direction in which it is moving.

It can also be described as the instantaneous rate of change of the particle's distance traveled.

To calculate the velocity we are using the formula here,

V= S/t

Here we are given,

S= a distance of a baseball thrown= 40m

t= time to travel the distance = 4 seconds.

Now we put the values in the above equation, we get

V= S/t

Or, V = 40/4

Or, V= 10m/s

So, from the above calculation we can conclude that, the velocity of a baseball thrown across a field is (V)= 10m/s

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The ratio of their time period is 1 : 2 : 2.

The momentum of a proton, a deuteron, and an alpha particle is the same in a uniform magnetic field.

The charge of a proton is q = e and the let m(p) be the mass of the proton.

Let m(d) = 2m(p) be the mass of the deuteron and the charge of a deuteron is q =e.

Now, an alpha particle is made up of 4 protons. Therefore the mass of an alpha particle is 4m(p) and the charge on an alpha particle is q = 2e.

The formula for the time period of a moving particle in a uniform magnetic field is given as:

[tex]T = \frac2 \pi m}{qB}[/tex] where B is the magnetic field, m is the mass and q is the charge of the particle.

So, the time period of a proton is:

[tex]T_{1} = \frac{2 \pi m(p)}{eB}[/tex]

The time period of a deuteron is:

[tex]T_{2} = \frac{2 \pi (2m(p))}{eB}[/tex]

And the time period of an alpha particle is:

[tex]T_{3} = \frac{2 \pi ( 4m(p) )}{2eB}[/tex]

Therefore, the ratio is:

[tex]T_{1}: T_{2} : T_{3} =\frac{2 \pi m(p)}{eB} : \frac{2 \pi 2m(p)}{eB} : \frac{2 \pi (4m(p))}{2eB}[/tex]

T₁ : T₂ : T₃ =  1 : 2 : 2

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Answer:

2.08 m  (2 d.p.)

Explanation:

Constant Acceleration Equations (SUVAT)

[tex]\boxed{\begin{array}{c}\begin{aligned}v&=u+at\\\\s&=ut+\dfrac{1}{2}at^2\\\\ s&=\left(\dfrac{u+v}{2}\right)t\\\\v^2&=u^2+2as\\\\s&=vt-\dfrac{1}{2}at^2\end{aligned}\end{array}} \quad \boxed{\begin{minipage}{4.6 cm}$s$ = displacement in m\\\\$u$ = initial velocity in ms$^{-1}$\\\\$v$ = final velocity in ms$^{-1}$\\\\$a$ = acceleration in ms$^{-2}$\\\\$t$ = time in s (seconds)\end{minipage}}[/tex]

When using SUVAT, assume the object is modeled as a particle and that acceleration is constant.

-------------------------------------------------------------------------------------

When a body is projected through the air with initial speed (u), at an angle of θ to the horizontal, it will move along a curved path.

Therefore, trigonometry can be used to resolve the body's initial velocity into its vertical and horizontal components:

Since the projectile is modeled as moving only under the influence of gravity, the only acceleration the projectile will experience will be acceleration due to gravity.

If the ball is kicked at an initial velocity of 20 m/s from flat ground at an angle of 45.9° then:

The horizontal component of velocity is constant, as there is no acceleration horizontally.

Resolving horizontally, taking → as positive:

[tex]s=35 \quad u=20 \cos 45.9^{\circ} \quad v = 20 \cos 45.9^{\circ} \quad a=0[/tex]

[tex]\begin{aligned}\textsf{Using} \quad s&=\left(\dfrac{u+v}{2}\right)t\\\\35&=\left(\dfrac{20 \cos 45.9^{\circ}+20 \cos 45.9^{\circ}}{2}\right)t\\35&=(20 \cos 45.9^{\circ})t\\t&=\dfrac{35}{20 \cos 45.9^{\circ}}\\\implies t&=2.51468288...\; \sf s\end{aligned}[/tex]

Therefore, the time is takes for the ball to reach the crossbar is 2.51 s.

Acceleration due to gravity = 9.8 ms⁻²

Resolving vertically, taking ↑ as positive:

[tex]u=20 \sin 45.9^{\circ} \quad a=-9.8 \quad t=2.51468288...[/tex]

[tex]\begin{aligned}\textsf{Using} \quad s&=ut+\dfrac{1}{2}at^2\\\\s&=(20 \sin 45.9^{\circ})(2.51468288...)+\dfrac{1}{2}(-9.8)(2.51468288...)^2\\s&=36.1171982...-30.9857870...\\\implies s&=5.131411132...\; \sf m\end{aligned}[/tex]

To find by how much the ball clears the crossbar, subtract the height of the crossbar (3.05 m) from found the vertical height of the ball at 2.51 s:

[tex]\implies 5.13141132...-3.05=2.08\; \sf m\;(2 \: d.p.)[/tex]

Therefore, the ball clears the crossbar by 2.08 m (2 d.p.).

The height reached by cat A is 2.5 m.

The speed of cat A before it hits the ground is 36.4 m/s.

The speed of cat B before it hits the ground is 22.39 m/s.

The time spent in air by cat A than cat B is 1.43 seconds.

The time of motion of cat A is calculated as follows;

h = vt - ¹/₂gt

-23 = 7t - 4.9t²

4.9t² - 7t - 23 = 0

solve the quadratic equation using formula method;

a = 4.9, b = -7, c = - 23

t = 3.0 seconds

The time of motion of cat B is calculated as follows;

h = vt - ¹/₂gt

23 = 7t + 4.9t²

4.9t² + 7t - 23 = 0

solve the quadratic equation using formula method;

a = 4.9, b = 7, c = -23

t = 1.57 seconds

h = u²/2g

h = (7²)/(2 x 9.8)

h = 2.5 m

v = u + gt

v = 7  + 3(9.8)

v = 36.4 m/s

v = u + gt

v = 7  + 1.57(9.8)

v = 22.39 m/s

Time difference = 3 s - 1.57 s = 1.43 seconds

Thus, the height reached by cat A is 2.5 m.

The speed of cat A before it hits the ground is 36.4 m/s.

The speed of cat B before it hits the ground is 22.39 m/s.

The time spent in air by cat A than cat B is 1.43 seconds.

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Electron and proton have rest energy which is option (a) and (c) .

According to Einstein's quantum theory light propagates in the form of packets i.e. quanta of energy, which is called photon.

The rest mass of photons is being zero. So photos do not have rest energy they are never at rest .

As electrons and protons posses mass , therefore they have rest energy which is given by [tex]E=mc^2[/tex] .

Hence , only electron and proton have rest energy not photon.

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Answer: 1.2 x 10^7kg

Explanation:

Volume of tank = length x width x height

Volume = 51 x 20 x 11

Volume = 11220 m^3

Density = Mass/Volume

Density = 1030 kg/m^3

Volume = 11220 m^3

Mass = m

1030 = m/11220

m = 1030 x 11220

m = 11,556,600 kg or 1.2 x 10^7kg

Answer:

0.9964

Explanation:

I think that's the right answer but here you go always!