A car of mass 750 kg accelerates away from traffic lights. At the end of the first 100 m it has reached a speed
of 12 m/s. During this time, its engine provides an average forward force of 780 N, and the average force of
friction on the car is 240 N.
a Calculate the work done on the car by the force of its engine.
b Calculate the work done on the car by the force of friction.
c Using ke. = mv2, calculate the increase in the car's kinetic energy at the end of the first 100 m.
d Explain whether your answers are consistent with the principle of conservation of energy.​

Most cells are so small that they can be observed only through a microscope is a scientific theory. Option A is correct.

A well-considered explanation for observations of the natural world that has been developed through the scientific method and that combines numerous facts and hypotheses is known as a theory.

A scientific hypothesis states that most cells are so tiny that a microscope is the only way to see them.

Hence option A is correct.

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The total length of the wire required is 63 m.

The current is the stream of charges which flow inside the conductors when connected across the end of voltage.

Given is a solenoid is configured to produce a magnetic field of 0.027T at its center. it has radius 1.4 cm and length 40cm and the wire can carry a maximum current of 12.0 A.

Radius, r = 1.4cm = 0.014 m

Length l = 40 cm = 0.4 m

If the current is I, then the magnetic field in solenoid is given by

B =  μ₀ n I

By substituting the values, we get

0.027 = 4π x 10⁻⁷ x n x 0.4

n = 1792 turns/unit length

Total length of wire = circumference x Turns

L = 2πr x N

where N = nl

Plug the values, we get

L = 2π x 0.014 x1792 x 0.4

L = 63 m

Thus, the total length of the wire is 63 m.

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To make the solute dissolve, thoroughly mix and add a little quantity of solvent after transferring the solute to a container

A solute is a material dissolved in another substance known as a solvent in a homogeneous mixture made of two or more components.

A solute's concentration in a solution is a measure of how much of that solute is dissolved in the solvent and the amount of solvent present, such as salt. Solutes are the best cleaning agents and additives.

Add a little quantity of solvent after transferring the solute to a container ideally a volumetric flask,

Which most precisely measures the volume of the solution indicated on the flask. To make the solute dissolve, thoroughly mix.

Hence the above process should be followed to dissolve, and thoroughly mix.

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Answer:

4.167

Explanation:

ittravels 4.167metres per second

Matter falling into a black hole arranges itself in the shape of a disk that is thick at the outer edge, thin along the inner ring.

A black hole is a region of space time where gravity is so strong that nothing or  no particles or even electromagnetic radiation such as light can escape from it.

Thus, matter falling into a black hole arranges itself in the shape of a disk that is thick at the outer edge, thin along the inner ring.

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The body's mass and velocity are multiplied to create momentum. It happens as a result of the force used. Kg m/s² is its unit. Measurement of mass in motion is momentum.

The body's mass and velocity are multiplied to create momentum. It happens as a result of the applied force and has the unit Kg-m/s².

Equal amounts of force and momentum are applied. More quantitative than the first rule of motion, the second law of motion is usually used to describe what happens when a force is applied.

The momentum is found as;

P =mv

Where m is the mass in kilogram

v is the velocity in m/sec

P is the momentum in the kg-m/s²

The second law of motion is more quantitative, and it is frequently used to quantify what occurs when a force is applied. The second law of Newton is discussed in depth in this article.

Force and the rate of change of momentum are equal. The force is given as the product of mass and change of velocity. The impulsive force is given by the change in momentum.

I=ΔP

Hence, the body's mass and velocity are multiplied to create momentum.

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Answer: yes it cannot be 100% efficient

Explanation:

only an ideal machine with 0 friction can have 100 percent efficiency

The energy input would it take to climb a ladder will be 20000 J.

Mechanical advantage is a measure of the ratio of output force to input force in a system, it is used to obtain the efficiency of the given mechanical machine.

Mechanical advantage is a measure of how much a machine multiplies the input force.

The complete question is;

"if we assume a typical efficiency of 25% for the human body how much energy input would it take to climb a ladder increasing body potential energy by 5000J"

The formula for the efficiency is;

[tex]\rm E = \frac{P}{\eta} \\\\ E = \frac{5000}{0.25} \\\\ E = 20000 \ J[/tex]

Hence, the energy input would it take to climb a ladder will be 20000 J.

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Answer:

D

Explanation:

PCN was discovered in mold

Answer:

convex lense

Explanation:

people with hyperopia or hypermetropia are long sighted or farsighted, so what happens here is that light doesn't focus on the surface of the retina but behind it so the picture is moved forward by positioning a convex lense in front of a hypermetropic eye and is correctly centered in the retina.

The likely outcome when a hyperpolarizing and a depolarizing potential of similar magnitudes arrive simultaneously at the trigger zone is the cancellation of charges.

Membrane action potential refers to differential electric charges within and outside of a given cell.

Hyperpolarization refers to a differential membrane potential of a cell associated with a negative charge, whereas depolarization is associated with a positive charge.

In conclusion, the likely outcome when a hyperpolarizing and a depolarizing potential of similar magnitudes arrive simultaneously at the trigger zone is the cancellation of charges.

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Answer:

a single closed path of electrical components including a voltage source

Answer:

Explanation:

Comment

The main points are that

Solution

               40 miles west

<==========================   0

=====================================================>

                                                  Displacement (30 km east)

Answer

30 km east                

The  direction the BASEBALL which is traveling in projectile motion is going is called a parabola.

Projectile motion is the motion of an object launched into the air at an angle to the horizontal and allowed to fall freely under the effect of gravity.

The  object is known as a projectile, and the path of motion is a curved path called a parabola.

Therefore, the direction the BASEBALL which is traveling in projectile motion is going is called a parabola.

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The velocity of the ball at position A is 3.13 m/s.Since all energy is converted to KE.

The potential energy is due to the virtue of the position and the height. The unit for the potential energy is the joule.

A person has the most potential energy due to her position. when he is sitting on the highest point.

Given data;

Mass,m = .5 kg

Height,H = 0.5 m

Acceleration due to gravity,g = 9.8 m/s²

H is the height

The potential energy is found as;

The potential energy is mainly dependent upon the height of the object.

Potential energy = mgh

The potential energy at point B;

PE = mgh

PE = ( 1.5 kg) ( 9.8 m/s2) (0.5 m)

PE = 7.35 J

Since all energy is converted to KE, the kinetic energy at point B;

KE = 0.5mv^2

KE = PE

7.35 = 0.53(1.5) v^2

V = 3.13 m/s

Hence, the velocity of the ball at position A is 3.13 m/s.

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Answer:

What is freezing point?

A liquid's freezing point is determined at which it turns into a solid. Corresponding to the melting point, the freezing point often rises with increasing pressure. In the case of combinations and for some organic substances, such as lipids, the freezing point is lower than the melting point. The first solid which develops when a combination freezes often differs in composition from the liquid, and the development of the solid alters the composition of the remaining liquid, typically lowering the freezing point gradually. Utilizing successive melting and freezing to gradually separate the components, this approach is used to purify mixtures.

What is melting point?

The temperature at which a purified substance's solid and liquid phases may coexist in equilibrium is referred to as the melting point. A solid's temperature goes up when heat is added to it until the melting point is achieved. The solid will then turn into a liquid with further heating without changing temperature. Additional heat will raise the temperature of the liquid once all of the solid has melted. It is possible to recognize pure compounds and elements by their distinctive melting temperature, which is a characteristic number.

The difference between freezing point and melting point:

Reference: Berry, R. Stephen. "When the melting and freezing points are not the same." Scientific American 263.2 (1990): 68-75.

The velocity is 6.75

The velocity in the equation stated above can be calculated as follows

m= 2,000
p= 2.25

y= 6000

velocity= 2.25 × 6000/ 2000
= 13500/2000
= 6.75

Hence the velocity is 6.75

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Explanation:

The correct is A.

every magnet have two pole

Given that a ball is thrown into the air and its height in feet after t seconds is given by y = 45t - 15t²,  the instantaneous velocity when t=4 is -75ft/s.

Given that;

First, we determine the derivative of y = 45t - 15t²

y' = (1)45 - (2)15t

y' = 45 - 30t

We substitute in t = 4

y' = 45 - 30t

y' = 45 - 30(4)

y' = 45 - 120

y' = -75ft/s

Given that a ball is thrown into the air and its height in feet after t seconds is given by y = 45t - 15t²,  the instantaneous velocity when t=4 is -75ft/s.

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Answer:

don't exist

Explanation:

A. The final temperature of the system is 0°C.

B. The amount of ice (if any) remaining is  0.0331 g

C. The initial temperature of the water that would be enough to just barely melt all of the ice is 20.57 °C.

The specific heat is the amount of heat required to change the temperature by 1°C. It is denoted by C.

Heat lost or gained is represented as

Q = m C ΔT

Given, Mass of ice, mice = 9x10⁻² kg, Mass of water, mw =0.35 kg, T = 13 °C

A. If ice is in excess, final water temperature will be 0°C.

B. Specific heat of water Cp = 1000 cal/kg°C

Latent heat of ice L = 80 kcal/kg

In that case, heat lost by water =Heat gain by ice

Q = mCp x dT = mL

0.35 x 1000 x 13 = m x 80 x 1000

m = 0.0569 kg of ice.

The gram of ice remaining = 0.09 - 0.0569

                                             = 0.0331 gram of ice.

Thus,  the amount of ice remaining is 0.0331 g

C. Heat required to melt 90 gram of ice,  Q  mL

Q = 90 x 80 = 7200 cal.

If the initial temperature of water needed = T,

mCp x dT = mL

350 x T = 7200

T = 20.57 °C

Thus,  the initial temperature of the water that would be enough to just barely melt all of the ice is  20.57 °C.

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Answer:

h = 4.25 m

Explanation:

[tex]gravitational \space\ potential \space\ energy \space\ (gpe)= m g h\\[/tex] ,

where m is the mass, g is acceleration of gravity, and h is height of object.

In our case, m = 1.2 kg, g = 9.8m/s², and gpe = 50 J.

50 = 1.2 x 9.8 x h

h = 50 / (1.2 x 9.8)

h = 4.25 m

Answer:

4.25m

Explanation:

Joules is a "derived unit", meaning it is really composed of other units, and it is just abbreviated as a single letter.

[tex]1[J]=1 [\frac{kg \cdot m^2}{s^2}][/tex]

This comes from the formula for potential energy, often denoted "U"

[tex]U=mgh[/tex], where m is the mass of the object (measured in kilograms,  [tex]kg[/tex]), g is the acceleration due to gravity at that spot (measured in meters per second squared,  [tex]\frac {m}{s^2}[/tex]), and h is the height of the object (measured in meters, [tex]m[/tex]).

Note:  The object itself may or may not have an acceleration of "g" at the given point because it may be supported (like on a bookshelf).  However, the "g" is representative of its gravitational acceleration at that point if gravity could accelerate it unimpeded.

Rearranging the potential energy equation to isolate the unknown "h", dividing both sides by "m" and "g", we get the following:

[tex]\dfrac{U}{mg}=h[/tex]

Substituting known values (and rewriting Joules as its SI units so we can ensure units cancel the way we need them to):

[tex]\dfrac{\left (50 [\frac{kg \cdot m^2}{s^2}] \right)}{(1.2 [kg])(9.8 [\frac{m}{s^2}])}=h\\\dfrac{\left (50 [\frac{kg \!\!\!\!\!\!\!{--} \cdot m^{2 \!\!\!{-}}}{s^2\!\!\!\!\!\!\!{--} }] \right)}{(1.2 [kg \!\!\!\!\!\!\!{--} ])(9.8 [\frac{m\!\!\!\!\!\!\!{--} }{s^2\!\!\!\!\!\!\!{--} }])}=h\\\dfrac{(50)}{(1.2)(9.8)}[m]=h\\\\4.2517[m] \approx h[/tex]

Thus, the height of the book would be approximately 4.25meters high.

The formula that can be used to obtain a convergent series is given by;

a/1 – r.

In mathematics, we define a series as sum of numbers which could be convergent or divergent. In a convergent series, the summation of the numbers approaches a given value.

The formula that can be used to obtain a convergent series is given by;

a/1 – r.

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Answer:

M. Magnetism is a property of individual atoms.

Explanation:

when a magnet is broken into pieces the new pieces behave like the original magnet this observation shows that magnetism is the property of individual atoms.

Taking into account the definition of pH and pOH, the concentration of H⁺ ions at pH=8 is 1×10⁻⁸ M and the concentration of OH⁻ ions at pH=8 is 1×10⁻⁶ M.

pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:

pH= - log [H⁺]= - log [H₃O⁺]

Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:

pOH= - log [OH⁻]

The following relationship can be established between pH and pOH:

pOH + pH= 14

In this case, pH=8. Replacing in the definition of pH:

8= - log [H⁺]

Solving:

[H⁺]= 10⁻⁸= 1×10⁻⁸ M

Finally, the concentration of H⁺ ions at pH=8 is 1×10⁻⁸ M.

Being pH= 8, pOH is calculated as:

pOH + 8= 14

pOH= 14 - 8

pOH= 6

Replacing in the definition of pOH the concentration of OH⁻ ions is obtained:

- log [OH⁻]= 6

Solving

[OH⁻]= 10⁻⁶= 1×10⁻⁶ M

Finally, the concentration of OH⁻ ions at pH=8 is 1×10⁻⁶ M.

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The statement which best describes Deena's error is: B. Include the area of the rectangle under the line to find displacement for constant acceleration.

A velocity vs. time graph can be defined as a type of graph that is used to graphically represent the rate of change of velocity of an object with respect to time.

Based on the information provided in the table shown (see attachment), the statement which best describes Deena's error is her not including of the area of the rectangle under the line, so as to enable her find displacement for constant acceleration.

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Complete Question:

Deena made a chart to summarize features of a velocity vs. time graph for objects with constant acceleration and objects with constant velocity.

Which best describes Deena's error?

A. The line for constant velocity is not horizontal; it is diagonal and slopes downward.

B. Include the area of the rectangle under the line to find displacement for constant acceleration.

C. Find acceleration by finding the area of the rectangle above the line.

D. Find velocity by calculating the slope of the line.