Select the statement that is true regarding scientific theories.
A. Scientific theories are what laws are called before they are proven.
B. Scientific theories attempt to explain why natural events occur.
C. Scientific theories are based on true facts.
D. Scientific theories describe natural events.

There will be two different possiblites as

May be one is in rest or other move

May be both will be in motion

According to Conservation Law of Momentum, when the two objects collide with each other, they transferred their kinetic energy to keep their momentum before or after collisions remain constant. In the present example, one moving car collides with another car which is at rest and has the same weight. There will be two possibilities after the collision as an elastic collision or perfect inelastic collision. In the elastic collision, the one car will adopt the rest position after the collision and transfer it K.E to make the rest car at the movable position. In the perfect inelastic collision, both cars will move after the collision.

Answer:

It attains the same speed as the first car.

Answer:

Electromagnetic energy/force

Explanation:

Electromagnetism: Electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. It combines electrostatics and magnetism, distinct but closely intertwined phenomena. The electromagnetic force is dominant in the interactions of atoms and molecules.

Electric Forces: Electric forces cause attraction between particles with opposite charges and repulsion between particles with the same charge. These forces are described by Coulomb’s law for electricity.

Magnetic Forces: Magnetism arises from the interaction between charged particles in relative motion. The magnetic force acts perpendicular to both the velocity of the charged particle and the magnetic field.

Applications: Electromagnetism plays a vital role in technology, including electrical energy production, communication (fibre optics and wireless), sensors, computation, and mechanical motors. It also explains chemical bonding and the behaviour of atoms and molecules.

In summary, electromagnetic force governs the behaviour of charged particles and underpins much of our understanding of the physical world

vector A has magnitude 12 m and direction +y

so we can say

[tex]\vec A = 12 \hat j[/tex]

vector B has magnitude 33 m and direction - x

[tex]\vec B = -33 \hat i[/tex]

Now the resultant of vector A and B is given as

[tex]\vec A + \vec B = 12 \hat j - 33 \hat i[/tex]

now for direction of the two vectors resultant will be given as

[tex]\theta = tan^{-1}\frac{12}{-33}[/tex]

[tex]\theta = 160 degree[/tex]

so it is inclined at 160 degree counterclockwise from + x axis

magnitude of A and B will be

[tex]R = \sqrt{A^2 + B^2}[/tex]

[tex]R = \sqrt{12^2 + 33^2} = 35.11 m[/tex]

so magnitude will be 35.11 m

Final answer:

The direction of the resultant vector A› + B› is 20.1° north of the negative x-axis, and its magnitude is approximately 35.1 m.

Explanation:

To find the direction and magnitude of the resultant vector A› + B›, we can use vector addition. Vector A› points in the positive y direction and has a magnitude of 12 m, so its components are (0, 12). Vector B› has a magnitude of 33 m and points in the negative x direction, with components (-33, 0). By adding these components, we get the resultant vector R = A + B = (0 - 33, 12 + 0) = (-33, 12).

To find the magnitude of the resultant vector, we use the Pythagorean theorem:

|R| = √((-33)^2 + (12)^2) = √(1089 + 144) = √(1233) ≈ 35.1 m

The direction of resultant vector R can be found by calculating its angle θ with respect to the negative x-axis (since the x component is negative) using the tangent function:

θ = arctan(|12| / |-33|) = arctan(12 / 33) ≈ 20.1°

The direction is therefore 20.1° above (north of) the negative x-axis.

the force that resists the movement of a solid object through a fluid (liquid or gas). Hope this helps.

Fluid friction, or drag, is the force resisting the motion of an object through a fluid like water or air. It depends on factors such as fluid viscosity, object shape and speed, and contact surface area. Examples include a boat moving through water and air resistance on a falling parachutist.

Fluid friction, also known as drag, is the force that opposes the motion of an object through a fluid (liquid or gas). This type of friction occurs when layers of the fluid move at different speeds or directions. For instance, a boat moving through water experiences fluid friction between the hull and the water, which resists its motion.

Fluid friction is influenced by several factors, including the viscosity of the fluid, the shape and speed of the object, and the surface area in contact with the fluid. An example of this is air resistance, which acts on a parachutist falling through the atmosphere, slowing their descent due to the opposition force of the air.

semiconductors ... silicon, germanium etc ...

Answer:

Semiconductors

Explanation:

The resistivity of conductors is low and the resistivity of insulators is high. The materials having resistivity between conductors and insulators are called semiconductors.

For example, silicon, gemanium, etc.

The elements having valency +4 are the semiconductors.

By increasing the temperature os a semiconductor, the conductivity increases or by the process of dopping the conductivity of semiconductor also increases.

F = ma

=   70kg ×  5ms⁻²

F =350N  

The sprinter is exerting a force of 350 Newtons.

The force exerted by the sprinter can be calculated using Newton's second law, which states that force is equal to mass multiplied by acceleration. In this case, the sprinter's mass is 70 kg and the acceleration is 5 m/s². So, the force exerted by the sprinter is:

Force = mass x acceleration

Force = 70 kg x 5 m/s²

Force = 350 N

Therefore, the sprinter is exerting a force of 350 Newtons.

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A chemical reaction produced a gas. I use to make rockets with baking soda and vinegar. Just put the 2 together and jam a plug in the top and the gas will shoot it into the air.

Answer:

 Height of coffee mug = 5 cm

Explanation:

  Changing all the data given in to unit cm

              50 mm = 5 cm

              20 cm  = 20 cm

              8 m    = 800 cm

              0.1 km = 100 m = 10000 cm

Since we need to find the height of coffee mug, it's height will not be more than 10 cm.

  So 5 cm is the correct choice.

dependent volume and mass and independent melting point and bowing point

The two size dependent properties of iron are Volume and Mass and size independent properties are Melting point and Boiling point respectively.

The given problem is based on the properties of iron nail. The iron nails are made of steel and small amount of carbon for increasing the hardness.

The two size dependent properties of iron nails are as follows:

The size independent properties of the iron nails are as follows:

Thus, we can conclude that the two size dependent properties of iron are Volume and Mass and size independent properties are Melting point and Boiling point respectively.

Learn more about the composition of iron here:

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Gravity is the force that causes acceleration. Friction is a force that opposes motion, energy is a capacity to do work, and velocity is a measure of speed in a specific direction.

Of the forces listed in your question, it is the force of gravity that causes acceleration. For example, when an object is dropped, it accelerates toward Earth under this force. This is popularly known as the force of gravity and represented as 'g'. The rate of acceleration due to gravity on Earth is approximately 9.81 m/s². Friction, on the other hand, actually opposes motion and may cause deceleration, if it is the only force acting on an object. Energy is a capacity to do work and does not directly cause acceleration, while velocity is a measure of speed in a specific direction and is a result, not a cause, of acceleration.

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The correct answers are:

- is repulsive

- produces light

- produces electricity

Explanation:

The electromagnetic force can be either attractive (when the two charges have opposite sign) or repulsive (when the two charges have same sign). On the contrary, the gravitational attraction is always attractive, so "is repulsive" is a property of the electromagnetic force only.

Moreover, as a result of electromagnetic interactions, photons can be produced (so, light, since light consists of photons), as well as electrons or other charged particles (so, electricity, since electrical currents consists of electrons or charged particles), while the gravitational force is not able to produce light or electrical currents.

If Val is comparing the gravitational force and the electromagnetic force, what applies is:

Electric and Magnetic Interaction: The electromagnetic force encompasses both electric and magnetic interactions. It is responsible for electric attraction and repulsion between charged particles and the behavior of magnets.

2. Acts on Charged Particles: The electromagnetic force acts on charged particles, which can be positively charged (protons), negatively charged (electrons), or both. Like charges repel each other, while opposite charges attract.

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Answer:

Nickel - Transitional Metal

Potassium- Alkali Metal

Cadmium- Transitional Metal

Calcium- Alkaline Earth Metal

Barium- Alkaline Earth Metal

Explanation:

Answer:

Nickel - Transitional Metal

Potassium- Alkali Metal

Cadmium- Transitional Metal

Calcium- Alkaline Earth Metal

Barium- Alkaline Earth Metal

Explanation:

The solution is attached below.

Answer:

Range of arrow = 225.09 meter

Final horizontal velocity = 34.47 m/s

Explanation:

We have equation of motion [tex]s=ut+\frac{1}{2} at^2[/tex], where u is the initial velocity, t is the time taken, a is the acceleration and s is the displacement.

Considering the vertical motion of arrow ( up direction as positive)

   We have u = 45 sin40 = 28.93 m/s, s = -20 m, a = acceleration due to gravity = [tex]-9.8m/s^2[/tex].

   [tex]-20=28.93*t-\frac{1}{2} *9.8*t^2\\ \\ 4.9t^2-28.93t-20=0[/tex]

   t = 6.53 seconds or t = -0.63 seconds

   So time = 6.53 seconds.

Considering the horizontal motion of arrow

   u = 45 cos 40 = 34.47 m/s, t = 6.53 s, a = [tex]0m/s^2[/tex]

   [tex]s=34.47*6.53+\frac{1}{2} *0*6.53^2\\ \\ s=225.09m[/tex]

So range of arrow = 225.09 meter

Horizontal velocity will not change , final horizontal velocity = 34.47 m/s.

mass of the chair = 25 kg

Force required to start the motion = 165 N

Force required to maintain the motion = 127 N

part a)

when we applied the force to just start the motion then it is just equal to the limiting friction force

[tex]F_s = F[/tex]

now as we know that

[tex]\mu_s mg = 165[/tex]

[tex]\mu_s * 25 * 9.8 = 165[/tex]

[tex]\mu_s = \frac{165}{25*9.8}[/tex]

[tex]\mu_s = 0.67[/tex]

PART b)

when object has started motion then to maintain its motion we need external force to balance kinetic friction  

[tex]F_k = F[/tex]

now as we know that

[tex]\mu_k mg = 127[/tex]

[tex]\mu_k * 25 * 9.8 = 127[/tex]

[tex]\mu_k = \frac{127}{25*9.8}[/tex]

[tex]\mu_k = 0.52[/tex]

I believe the answer is 56000 kgm/s

I'm pretty sure the answer is the gravitational pull  increases

Answer:

if we increase the mass gravitational pull increases

Explanation:

According to gravitational law

Force between masses is given by [tex]F=\frac{Gm_1m_2}{R^2}[/tex], here G is gravitational constant [tex]m_1\ and\ m_2[/tex] are masses and R is distance between them

From the relation we cans see that gravitational pull is directly proportional to mass of the object

So if we increase the mass gravitational pull increases

Answer:

2

Explanation:

The first person to answer was right

50 kilometers should be it

Answer:

13.89 m/s

Explanation:

Velocity=Displacement/Time

Explanation:

75 km = 75000 m

1.5 hours = 5400 sec

Applying the formula

Velocity =75000 m 5400 s = 13.89 m/s

initial speed of the stuntman is given as

[tex]v = 28 m/s[/tex]

angle of inclination is given as

[tex]\theta = 15 degree[/tex]

now the components of the velocity is given as

[tex]v_x = 28 cos15 = 27.04 m/s[/tex]

[tex]v_y = 28 sin15 = 7.25 m/s[/tex]

here it is given that the ramp on the far side of the canyon is 25 m lower than the ramp from which she will leave.

So the displacement in vertical direction is given as

[tex]\delta y = -25 m[/tex]

[tex]\delta y = v_y * t + \frac{1}{2} at^2[/tex]

[tex]-25 = 7.25 * t - \frac{1}{2}*9.8* t^2[/tex]

by solving above equation we have

[tex]t = 3.12 s[/tex]

Now in the above interval of time the horizontal distance moved by it is given by

[tex]d_x = v_x * t[/tex]

[tex]d_x = 27.04 * 3.12 = 84.4 m[/tex]

since the canyon width is 77 m which is less than the horizontal distance covered by the stuntman so here we can say that stuntman will cross the canyon.

A time-varying magnetic field can be caused by fluctuating electric fields.

Answer:

-fluctuating electric fields

Explanation:

As we know that electric field and magnetic field is related by the equation given as

[tex]\int E. dl = -\frac{d\phi}{dt}[/tex]

here we know that

[tex]\phi = B.A[/tex]

now we have magnetic field is time varying

[tex]\int E.dl = -A\frac{dB}{dt}[/tex]

now for closed loop of radius "r" we will have

[tex]E(2\pi r) = - A\frac{dB}{dt}[/tex]

[tex]E = -\frac{A}{2\pi r}\frac{dB}{dt}[/tex]

so here this produce electric field as per above formula and it is also known as non conservative electric field.

Answer:

No, its not reasonable.

Explanation:

The substance that is to be dissolved is known as solute. The substance that is dissolving is known as solvent.

The amount of solvent  in the mixture should be greater than that of solute.

Suppose we are taking a solvent in a beaker and we are continuously adding solute in it. Initially the solute dissolve quickly. At some point the solute stops dissolving in the solvent. This is known as saturation point of the solvent. After saturation point if solute is added further it does not dissolve in the solvent.

So, its not possible to dissolve 12.8 g of one substance in 11 g of another.

As per doppler's Effect of sound we can say when subway is approaching the platform we will have

[tex]f_1 = f_o* \frac{v}{v- v_s}[/tex]

[tex]12750 = f_o* \frac{340}{340 - v_s}[/tex]

Similarly we can find the frequency when subway is passing away with same speed from us

[tex]f_2 = f_o* \frac{v}{v + v_s}[/tex]

[tex]10750 * f_o* \frac{340}{340 + v_s}[/tex]

now we can find the ratio of two

[tex]\frac{12750}{10750} = \frac{340 + v_s}{340 - v_s}[/tex]

[tex]1.186*(340 - v_s) = 340 + v_s[/tex]

[tex]403.26 - 1.186 v_s = 340 + v_s[/tex]

[tex]63.26 = 2.186 v_s[/tex]

[tex]v_s = \frac{63.26}{2.186}[/tex]

[tex]v_s = 28.94 m/s[/tex]

So the speed of subway is 28.94 m/s

Answer:

The answer is 0.39 m/s ²

Explanation:

Since the box moves with steady speed,  

Friction=force in even direction=260*Cos20=244.3N  

Ordinary force=mg+FSinθ=1089N  

μN=f  

μ=244.3/1089=0.224  

N=mg-FSinθ=911.1N  

a=(260 Cos20-0.224*911.1)/(1000/9.8)=0.39m/s²

It would be alto. I hope that is one of your answers.

Which cloud type is confined to the middle height range?

A.  cumulonimbus

B.  cirrus

C.  cirrostratus

D.  altostratus

Answer:

D.  Altostratus

Explanation:

Altostratus cloud is a type of physical stratiform: a cloud which can be identified by its gray or blueish gray colour. It is a middle level cloud, that is associated with a storm and excessive rain or snow. It contains ice crystals and water droplets, and it is lighter in colour when compared to nimbostratus, while it is darker in appearance when compared to cirrostratus.

The answer would be 0.04ohms.

Answer:

The resistance of an electric device is 0.04 ohms.

Explanation:

Given that,

Resistance = 40,000 micro ohms

We need to convert micro ohms to ohms

We know that,

[tex] 1 micro ohms = 10^{-6}\ ohms[/tex]

Therefore,

[tex]40000\ micro ohms=40000\times10^{-6}\ ohms[/tex]

[tex]40000\ micro ohms=0.04\ ohm[/tex]

Hence, The resistance of an electric device is 0.04 ohms.

The answer is Absorption.

The Absorption one

and im writing more cause 20 character thing

Here refrigerator removes 55 kcal heat from freezer

Refrigerator releases 73.5 kcal heat to surrounding

So here we can use energy conservation principle by II Law of thermodynamics

the law says that

[tex]Q_1 = Q_2 + W[/tex]

here we know that

[tex]Q_1[/tex] = heat released to the surrounding

[tex]Q_2[/tex] = heat absorbed from freezer

W = work done by the compressor

now using above equation we can write

[tex]73.5 = 55 + W[/tex]

[tex]W = 73.5 - 55[/tex]

[tex]W = 18.5 kcal[/tex]

So here compressor has to do 18.5 k cal work on it

Final answer:

The work done by the refrigerator's compressor, when it removes 55.0 kcal of heat from the freezer and releases 73.5 kcal through the condenser, is calculated to be 77,464 joules, after converting kcal to joules.

Explanation:

To determine the work done by the compressor in a refrigerator when it removes 55.0 kcal of heat from the freezer and releases 73.5 kcal through the condenser on the back, we can use the principle of conservation of energy. According to the first law of thermodynamics, the energy extracted from the freezer plus the work done by the compressor equals the energy released into the environment through the condenser.

The work done by the compressor (W) can be calculated by subtracting the heat removed from the cold reservoir (Qc) from the heat added to the hot reservoir (Qh).

First, we need to convert the heat quantities from kcal to joules because the standard unit of energy in physics is the joule (J). 1 kcal = 4184 J, therefore:

Qc = 55.0 kcal * 4184 J/kcal = 230120 J

Qh = 73.5 kcal * 4184 J/kcal = 307584 J

Now, calculate the work done:

W = Qh - Qc = 307584 J - 230120 J = 77464 J

Therefore, the compressor performed 77464 J of work in this process.

A position-versus-time graph for motion with constant, nonzero acceleration forms a parabola, as the position increases at an increasing rate due to constant acceleration.

The shape of the graph for motion with constant, nonzero acceleration on a position-versus-time graph is a parabola. Acceleration - the rate of change of velocity - is constant in this scenario, implying that velocity is increasing at a constant rate. As a result, position, which is the area under the velocity versus time graph, increases at an increasing rate. This is represented graphically by a parabolic curve.

For instance, consider a car starting from rest and accelerating at a consistent rate. At the beginning of motion, the car covers a relatively small distance, resulting in a low point on the graph. As time progresses and the car accelerates, the distance covered in each subsequent time interval increases, resulting in an upward curve on the position-versus-time graph. The steepness of the curve increases with time, forming a parabolic shape.

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Speed of Ferry is towards North with magnitude 6.2 m/s

Here if we assume that North direction is along Y axis and East is along X axis then we can say

[tex]\vec v_f = 6.2 \hat j[/tex]

Now a person walk on ferry with speed 1.5 m/s towards east with respect to Ferry

so it is given as

[tex]\vec v_{pf} = 1.5 \hat i[/tex]

also by the concept of relative motion we know that

[tex]\vec v_{pf} = \vec v_p - \vec v_f[/tex]

now plug in all values in it

[tex]1.5 \hat i = \vec v_p - 6.2 \hat j[/tex]

[tex]\vec v_p = 1.5 \hat i + 6.2 \hat j[/tex]

now if we need to find the speed of the person then we need to find its magnitude

so it is given as

[tex]v = \sqrt{1.5^2 + 6.2^2}[/tex]

[tex]v = 6.37 m/s[/tex]