A ball is tied to the end of a length of string. A student holds one end of the string and whirls it so the ball travels in a vertical circle. First she whirls the ball at a very fast speed, and then she very gradually lowers the speed. Where is the ball most likely to be when the string begins to sag?

Answers

Answer 1

Answer:

The top of the circle

Explanation:

At the top of the circle, there are two forces pulling the ball towards the center of the circle: weight and tension.

∑F = ma

mg + T = mv²/r

As v goes down, T also goes down, until it eventually reaches 0.

At the bottom of the circle, weight is pulling down, or away from the center of the circle.  Sum of the forces:

∑F = ma

T − mg = mv²/r

As v goes down, T also goes down.  However, even at v=0, T cannot be less than mg.


Related Questions

plz help!!!
urgent!!
will give the brainliest!!!​

Answers

Answer: Find the answer in the explanation.

Explanation:

I.) A piece of wire at room temperature.

The resistance of a piece of wire at room temperature is independent of both current and the voltage because it is an Ohmic component.

II.) Filament bulb

The filament wire in the filament bulb does not obey Ohms law.

For very small currents and voltage, the graph is roughly a straight line. At higher voltages, the line starts to curve.

III.) A diode is any component that allows electric current in only one direction. The resistance of a diode depends on the potential difference across it. Therefore, it does not obey Ohms law. It is a non-Ohmic component.

Find the attached files for the figures

The frequency of which type of electromagnetic wave is just higher than that of radio waves? Infrared rays Ultraviolet rays X-rays Microwaves Gamma rays

Answers

Gamma-rays, the explanation and information is found in the image below.

Answer: gamma rays

Explanation:

Which point is labeled in the scatterplot below?​

Answers

It’s look like (8,3)

A 15.0 cm object is 12.0 cm from a convex mirror that has a focal length of -6.0 cm. What is the height of the image produced by the mirror? A. –5.0 cm B. 7.5 cm C. -7.5 cm D. 5.0 cm

Answers

Answer: D. 5cm

Explanation:

Given the following :

Focal length (f) = - 6.0 cm

Height of object = 15.0cm

Distance of object from mirror (u) = 12.0cm

Height of image produced by the mirror =?

Firstly, we calculate the distance of the image from the mirror.

Using the mirror formula

1/f = 1/u + 1/v

1/v = 1/f - 1/u

1/v = 1/-6 - 1/12

1/v = - 1/6 - 1/12

1/v = (- 2 - 1) / 12

1/v = - 3 / 12

v = 12 / - 3

v = - 4

Using the relation :

(Image height / object height) = (- image distance / object distance)

Image height / 15 = - (-4) / 12

Image height / 15 = 4 / 12

Image height = (15 × 4) / 12

Image height = 60 / 12

Image height = 5cm

Answer:

D. 5 cm

Explanation:got it right

What do you feel when you hold your hand near a glowing fire or an electric heater?

Answers

Answer:

The heats radiation.

Explanation:

When placing your hand close to a fire or electric heater, you can feel the warmth of the object. Pull your hand away from it, it'll be cooler.

Answer:

The radiation of heat

Explanation:

3. How do we measure the average kinetic motion of molecules in a solution?

Answers

The translational kinetic energy of of an ideal gas can be found by multiplying the formula for the average translational kinetic energy by the number of molecules in the sample.

In general, the the string or air column of a musical instrument is, the more harmonics are generated.

Answers

Answer:

In general, the LONGER the string or air column of a musical instrument is, the more harmonics are generated.

How is a voltmeter used in a circuit?
A. It is connected in series and measures current.
B. It is connected in parallel and measures potential difference.
C. It is connected in parallel and measures current.
D. It is connected in series and measures potential difference.

Answers

Answer:

Explanation:

A voltmeter is usually connected in parallel with a part of a complete circuit.  The meter itself is connected in series to a very high resistance so that the amount of current drained is very tiny.

So you see, you could answer this in two ways, but since you are asking a question at a very beginning level, I think the answer should be

B

because voltmeters are made to measure potential difference and they are placed in parallel to the part measured. How it works is interesting but is not really part of the question.

Answer:

B. It is connected in parallel and measures potential difference.

Explanation:

A voltmeter is connected in parallel.

A voltmeter is used for measuring the electrical potential difference between two points in an electric circuit.

An object moving north with an initial velocity of 14 m/s accelerates 5 m/s2 for 20 seconds. What is the final velocity of the object? 39 m/s 90 m/s 114 m/s 414 m/s

Answers

Answer:

Final velocity of the object(v) = 114 m/s

Explanation:

Given:

Initial velocity (u) = 14 m/s

Accelerates (a) = 5 m/s²

Time taken = 20 seconds

Find:

Final velocity of the object(v) = ?

Computation:

According to 1st law of motion.

⇒ v = u +at

⇒ v = 14 + (5)(20)

⇒ v = 14 + 100

⇒ v = 114 m/s

Final velocity of the object(v) = 114 m/s

Which explains the operation of a hydraulic lift system? A. Archimedes' principle B. Pascal's principle C. Newton's principle D. Bernoulli's principle

Answers

Answer: B. Pascal's principle

This is the idea where you compress a liquid on one end of a tube (more or less), and the liquid's pressure is transmitted to the other end to help lift a heavy object. Often the compressing force is downward to take advantage of gravity.

A lens is used to make an image of magnification -1.50. The image is 30.0 cm from the lens. What is the object’s distance (unit=cm)? PLS HELP

Answers

Answer: 20cm

Explanation:

Given the following data:

Magnification of image = - 1.50

Distance of image from the lens = 30.0cm

The Magnification of an image is the ratio of the image distance from the lens and the object distance from the lens.

Mathematically,

Magnification(M) = - (image distance (di) / object distance (do))

M = - (di/do)

-1.50 = - (30/do)

do = 30 / 1.5

do = 20 cm

Object is placed at a distance of 20cm from the lens.


Priscilla is driving her car on a busy street and Harvey passes her on his motorcycle. What will happen to the sound from his motorcycle after it
passes her car?

Answers

Answer:

what will happen to the sound is the wavelength increases thus frequency decreases so the sound decreases as he move away from her car..

A 51-kg woman runs up a vertical flight of stairs in 5.0 s. Her net upward displacement is 5.0 m. Approximately, what average power did the woman exert while she was running?

Answers

Answer:

The average power the woman exerts is 0.5 kW

Explanation:

We note that power, P = The rate at which work is done = Work/Time

Work = Energy

The total work done is the potential energy gained which is the energy due to vertical displacement

Given that the vertical displacement = 5.0 m, we have

Total work done = Potential energy gained = Mass, m × Acceleration due to gravity, g × Vertical height, h

m = 51 kg

g = Constant = 9.81 m/s²

h = 5.0 m

Also, time, t = 5.0 s

Total work done = 51 kg × 9.81 m/s²× 5 m = 2501.55 kg·m²/s² = 2501.55 J

P = 2501.55 J/(5 s) = 500.31 J/s = 500.31 W ≈ 500 W = 0.5 kW.

A deep-space satellite is sent to orbit a distant planet with unknown mass. On
arrival, the satellite begins its orbit and measures a gravitational pull from the
planet of 620 N. If the satellite has a mass of 450 kg and orbits the planet at a
radius of 4.0 x 10^6m, what is the approximate mass of the planet?(recall that G=6.7x10^-11 N•m2/kg^2.)

Answers

Answer:

The mass of the planet is [tex]3.29\times 10^{23}\ kg[/tex].

Explanation:

Given that,

The gravitational pull on the planet is 620 N

Mass of a satellite is, m₁ = 450 kg

Radius of a planet is [tex]4\times 10^6\ m[/tex]

We need to find the mass of the planet. Gravitational force is given by :

[tex]F=\dfrac{Gm_1m_2}{r^2}[/tex][tex]m_2[/tex] is the mass of the planet

[tex]m_2=\dfrac{Fr^2}{Gm_1}\\\\m_2=\dfrac{620\times (4\times 10^6)^2}{6.7\times 10^{-11}\times 450}\\\\m_2=3.29\times 10^{23}\ kg[/tex]

So, the mass of the planet is [tex]3.29\times 10^{23}\ kg[/tex].

48:09 Which best describes the first law of thermodynamics as compared to the second law of thermodynamics? The first law describes how thermal energy is conserved but not the direction it moves. The first law describes the direction thermal energy moves but not how it is conserved. The first law describes how thermal energy can be created but not how it can be destroyed. The first law describes how thermal energy can be destroyed but not how it can be created.

Answers

Answer:

A). The first law describes how thermal energy is conserved but not the direction it moves.

Explanation:

Thermodynamics is demonstrated as the branch of physics that deals with the associations or relationships between heat and other energy forms like mechanical, chemical, and electrical).

As per the question, the first law discusses that heat is a kind or form of energy and thus, processes associated with thermodynamics are subject to energy conservation principle. Therefore, heat energy can neither be destroyed nor created but rather transferred to one place to another and converted to and from other energy forms.

Thus, the first law of thermodynamics is distinct from the second law as 'the former describes how thermal energy can be conserved to and from other forms of energy and not the direction in which it moves' while the second law focuses on entropy. Therefore, option A is the correct answer.

The first law of thermodynamics describes the conservation of heat energy but not the direction it moves. Option A correct.

 

First law of Thermodynamics:

It states that the energy cannot be produced or destroyed it just change from one form to another.

Heat is a form of energy and thus, follow the energy conservation principle. So, heat can be change into mechanical energy.

The second law describe the direction of movement of heat.

Therefore, option A is the correct answer.

To know more about First law of Thermodynamics:

https://brainly.com/question/7107028

I have a test tomorrow and I can't find the definitions in my book so can you pls help me study by answering the following question? thnx! I will also mark the brainliest.

Answers

Answer:

See explanation

Explanation:

An element is a substance that cannot be chemically converted to another substance or broken down chemically into other substances.

Elements are represented by symbols. The symbol of an element may be the first one or two letters from its English or Latin name. For instance, the symbol of nitrogen is N. This symbol was derived from the first letter of its English name. The symbol for sodium is Na. This was derived from the first two letters of its Latin name, Natrium.

The periodic table is divided into horizontal rows called periods and vertical columns called groups. All members of the same period have the same number of electron shells while all members of the same group have the same number of valence electrons.

Metals are found towards the left hand side of the periodic table while non metals are found towards the right hand side of the periodic table. Metals looses electrons easily while nonmetals accepts electrons easily. Metals are good conductors of heat and electricity while non metals are poor conductors of heat and electricity.Metalloids have properties intermediate between those of metals and non metals and are found at the boarder line between metals and non metals in the periodic table. Metalloids include; silicon, boron, germanium, etc. The electrical conductivity of metalloids increases with temperature while the electrical conductivity of metals decreases with temperature.

What causes the particles within the nucleus of an atom to bond together? Question 12 options: electromagnetism gravity weak nuclear force strong nuclear force

Answers

Answer:

Strong nuclear force

Explanation:

The particles in the atom's nucleus bond together because there is a strong nuclear force between the protons and neutrons that attracts them to each other and binds together the nucleus.

The answer is a strong nuclear force

Reason why: The particles bond together because of the strong nuclear force between the neurons and protons

Which option describes a phase change

Answers

Answer:

b. Gasloine evaporating into the air

I tryed to answer

it would be gasoline because evaporation is occurring

Which of the following is an example of a primary source?
A. A dictionary definition of a science term
B. An article written by a scientist
C. A textbook written by a scientist
D. An encyclopedia entry about an experiment

Answers

Answer:

i think its no c.

a textbook written by a scientist. because its a first hand data.

An article written by a scientist is an example of a primary source. The correct option is option (B).

A primary source refers to an original, firsthand account or direct evidence of an event, topic, or research. It is created by individuals who directly participated in or witnessed the subject matter. An article written by a scientist would be considered a primary source as it typically presents the researcher's own observations, experiments, methodology, and conclusions.

It provides direct access to the original research and findings, making it an important source for scholarly and scientific purposes. In contrast, options A, C, and D are secondary sources that provide interpretations or summaries of information from primary sources.

Therefore, The correct option is an option (B).

To know more about the primary source:

https://brainly.com/question/24172115

#SPJ5

What would be the mass of the ball described in the photo?

Answers

Answer:

- Mass of the ball = 45 Kg

Explanation:

velocity attained by the ball:

  Distance/time= 54/9 = 6m/s (meter per sec)

As work done on ball = distance * force applied

                                   = 54*15

                                   =   810 J            -----------------  (i)

acc. to the conservation of energy:

work done  = kinetic energy + potential energy

                  =  1/2*m*[tex]v^{2}[/tex] + 0(as object is on ground)

                  = 1/2*m*[tex]6^{2}[/tex]

                   = 1/2*36*m

                   = 18*m                      ------------------- (ii)

∵,(i) =(ii)

18*m = 810

m=810/18

m= 45kg

A metallic rod has a length 1.5m and a diameter 0.2 cm. The rod carries a current of 5A

when a p.d of 75V is applied between its ends.

(a) Find the current density in the rod.

(b) Calculate the magnitude of the electric field applied to the rod.

(c) Calculate the resistivity and conductivity of the material of the rod.​

Answers

Answer:

Explanation:

Current density J = i / A where i is current and A is cross sectional area

J = 5 / π x ( .1 x 10⁻² )²

= 1.6 x 10⁶ A / m²

b )

electric field applied E = V / l where V is potential difference and l is lemgth of rod

E = 75 / 1.5

= 50 v / m

c )

J = σ E

J is current density , σ is conductivity and E is electric field .

1.6 x 10⁶ = σ  x 50

σ = 3.2 x 10⁴ Ω⁻¹ m⁻¹

Resistivity = 1 / σ

= 1 / 3.2 x 10⁴

= .3125 x 10⁻⁴

=3.125 x 10⁻⁵  Ω m

Which of the following elements are in this chemical reaction: Zn (s) + HCl (9) → ZnCl2 (s) + H2 ?
Multiple answers
Α. Η
B. CI
C. Zn
D. nCI​

Answers

Answer:

A, B and C

Explanation:

You are given the chemical equation.

The chemical reaction:

Zn (s) + HCl (9) → ZnCl2 (s) + H2

The elements involved are

Zinc, hydrogen and Chlorine.

That is, H, Cl and Zn

The Zinc is in solid form

While hydrochloric acid is in aqueous form.

The correct answers are A ,B and C

At which point does the planet have the least gravitational force acting on it?

Answers

Answer:

At which point does the planet have the least gravitational force acting on it?

Explanation:

In an elliptical orbit, when a planet is at its furthest point from the Sun, it is under the least amount of gravity, meaning that the force of gravity is strongest when it is closest.

Answer:

Point A

Explanation:

Recall that gravitational force is inversely proportional to the square of the distance between the 2 objects.

This means that the farther away the objects are from each other, the lesser their gravitational interaction will be.

In this case we can see that Point A is furthest away from the star, hence this will be the location with the least gravitational force from the star.

Rosa records the distance that a toy car rolls and the time it takes to cover the distance. What scientific practice is this? collecting data asking a question providing explanations communicating results

Answers

Answer:

collecting data

Explanation:

Data collection refers to a systematic method for gathering and analyzing information from a number of sources in order to provide a complete and reliable image of a subject region. The collection of data helps an individual or organization to answer specific questions, determine outcomes, and predicting future possibilities and outcomes. As per the question, rosa is collecting data about the distance and time of her toy car intrigued by the scientific query.

Answer:

A : Data

Explanation:

I’m doing the exam

If an electromagnetic wave has a frequency of 4.5 x 1018 Hz, what is its
wavelength? Use î=”. The speed of light is 3 * 108 m/s.
A. 1.5 x 10-26
B. 6.7 x 1026 m
C. 1.5 x 10-10 m
D. 6.7 * 10-11 m

Answers

Answer:

Wavelength of electromagnetic wave = 6.7 × 10⁻¹¹

Explanation:

Given:

Frequency of electromagnetic wave = 4.5 × 10¹⁸ Hz

Speed of light = 3 × 10⁸ m/s

Find:

Wavelength of electromagnetic wave

Computation:

⇒ Wavelength = Speed of light / Frequency

⇒ Wavelength of electromagnetic wave = 3 × 10⁸ / 4.5 × 10¹⁸

⇒ Wavelength of electromagnetic wave = 0.67 × 10⁻¹⁰

Wavelength of electromagnetic wave = 6.7 × 10⁻¹¹

Which statement describes a characteristic of a spiral galaxy?

O It is shaped like a pinwheel.

O It has no new star formation.

O It is made only of gases.

O It is smaller than other types of galaxies.​

Answers

Answer:

It is shaped like a pinwheel

Explanation:

That's the shape.

The shape is like a pinwheel, which best describes a characteristic of a spiral galaxy. So option 1 is correct.

What is a Spiral Galaxy?

The twisted clusters of stars and gas known as spiral galaxies, which are frequently formed of hot, young stars, have striking shapes. As opposed to the other two major groups of galaxy forms, elliptical and irregular, spiral galaxies make up the majority of the galaxies that astronomers have so far discovered.

A spiral galaxy is one that contains Earth and our solar system, such as the Milky Way.

Approximately 72% of the galaxies that have been spotted by scientists are spiral galaxies, according to a 2010 Hubble Space Telescope survey.

The arms that circle the galaxy are formed when the disc of stars orbiting the bulge divides. These spiral arms are rich in gas, dust, and newborn stars that shine brilliantly before dying suddenly.

Hence, the first option is correct that a spiral galaxy is shaped like a pinwheel.

To learn more about Spiral Galaxy :

https://brainly.com/question/13074009

#SPJ2

What is the wave speed of a wave that has a frequency of 50 Hz and a wavelength of 0.10 m? What is the frequency of a wave that has a wave speed of 20 m/s and a wavelength of 0.50 m?

Answers

Answer:

a) What is the wave speed of a wave that has a frequency of 50 Hz and a wavelength of 0.10 m?

5m/s

b) What is the frequency of a wave that has a wave speed of 20 m/s and a wavelength of 0.50 m?

40Hz

Explanation:

a) What is the wave speed of a wave that has a frequency of 50 Hz and a wavelength of 0.10 m?

Wave speed(v) = Frequency(f) × Wavelength (λ)

= 50Hz × 0.10m

=5m/s

b) What is the frequency of a wave that has a wave speed of 20 m/s and a wavelength of 0.50 m?

The formula for Frequency when given wave speed and wave length = Wave speed/ wave length

f = v/λ

Frequency = 20m/s ÷ 0.50m

Frequency = 40Hz

Answer:

40 Hz

Explanation:

Suppose the initial position of an object is zero, the starting velocity is 3 m/s and the final velocity was 10 m/s. The object moves with constant acceleration. Which part of a velocity vs. time graph can be used to calculate the displacement of the object?

the area of the rectangle under the line
the area of the rectangle above the line
the area of the rectangle plus the area of the triangle under the line
the area of the rectangle plus the area of the triangle above the line

Answers

Answer:

The area of the rectangle plus the area of the triangle under the line

Explanation:

In this case, the object moves with constant acceleration. Initial speed of the object is 0.

Equation of kinematics :

v = u +at

v = at

v is directly proportional to time. If means that the graph is straight line passing through origin. We know that area under v-t graph gives displacement. So, the correct option is (c).

Answer:

c) the area of the rectangle plus the area of the triangle under the line

Explanation:

edge2021

Which shows a decrease in fluid pressure? A. Water in a creek slows down as it enters a slow-moving river. B. Oxygen is compressed as it is put into a pressurized tank. C. A river speeds up when it moves into a narrower channel. D. A fan is turned on high speed to low speed.

Answers

Answer:

Option D.

A fan is turned from high speed to low speed.

Explanation:

It is important to note that air is also a fluid.

In a system, static pressure of air increases with the speed of rotation of the fan. This is because when the speed of the fan is increased, the force with which it is pushing the air molecules is increased. Since pressure is a relationship between force and area, the pressure of the air molecules will be increased.

Conversely, when the speed of the fan is reduced, the priming force on the air molecules will be reduced, hence the pressure of the air will drop.

This makes option D the correct option

Answer:

A

Explanation

Becasue the water level is decreasing

Ethan made a diagram to compare examples of the first and second laws of thermodynamics. What belongs in the areas marked X and Y?
X: The internal energy of a piston system increases
as heat is added and rises to a cool area
Y: As thermal energy is added to a container, some
of the energy is lost to the environment
X: As thermal energy is added to a container, some
of the energy is lost to the environment
Y: The internal energy of a piston system increases
as heat is added and rises to a cool area
X: A cold spoon placed in hot liquid gets warmer
Y: Thermal energy is converted to light energy
X: Thermal energy is converted to light energy
Y: A cold spoon placed in hot liquid gets warmer

Answers

Answer:

D: X: Thermal energy is converted to light energy

Y: A cold spoon placed in hot liquid gets warmer

Explanation:

j took the quiz

The first and second laws of thermodynamics are used to describe the process of heat transfer.

What are the laws of thermodynamics?

The laws of thermodynamics are laws that show the transfer of heat energy there are three laws of thermodynamics that guide heat transfer.

From the statements of the first and second laws of thermodynamics, the statements that fit into the circles are;

X: Thermal energy is converted to light energy

Y: A cold spoon placed in hot liquid gets warmer

Learn more about the laws of thermodynamics:https://brainly.com/question/3808473

#SPJ6

Other Questions
what is the term for the price of Kelly Blue Book considers to be the correct amount one should expect to pay for a car According to a nutrition coach, a 100 kg person should eat0.07 kg of protein. What percent of a person's body weight should they eatin protein? (round to 2 decimal places) * Graba una frase con cada uno de los siguientes tiempos. Puedes usar cualquier verbo.1. presente perfecto2. pasado perfecto3. futuro perfecto4. condicional perfecto The main reason George H.W. Bush was victorious in 1988 was the fact that he promised which of the following to voters? Q4 please for a branliest answer characteristic of society A shaman is a special person among an indigenous culture who is able to access the spirit worldA. TrueB. False Giovanni Da Palestrina is known for his... A. development of renaissance counterpoint B. gregorian chants and old English madrigals C. complex orchestral arrangements what is this answer5+(4)= please help 50 points and brainlist Read the following speech excerpt and then select the correct answer to the question below: President George W. Bushs speech to the troops on the USS Abraham Lincoln Our mission continues. Al-Qaida is wounded, not destroyed. The scattered cells of the terrorist network still operate in many nations, and we know from daily intelligence that they continue to plot against free people. The proliferation of deadly weapons remains a serious danger. The enemies of freedom are not idle, and neither are we. Our government has taken unprecedented measures to defend the homeland and we will continue to hunt down the enemy before he can strike. The war on terror is not over, yet it is not endless. We do not know the day of final victory, but we have seen the turning of the tide. No act of the terrorists will change our purpose, or weaken our resolve, or alter their fate. Their cause is lost. Free nations will press on to victory. Other nations in history have fought in foreign lands and remained to occupy and exploit. Americans, following a battle, want nothing more than to return home. And that is your direction tonight. After service in the Afghan and Iraqi theaters of war after 100,000 miles, on the longest carrier deployment in recent history you are homeward bound. Some of you will see new family members for the first time 150 babies were born while their fathers were on the Lincoln. Your families are proud of you, and your nation will welcome you. How is the third paragraph different from the first two? It no longer sounds authoritative or informed about the situation. It broadens its view to consider the service people around the world. It gets more specific by talking about the service people on the USS Lincoln. It comes across as unfeeling and insensitive to the people who have suffered. I could use some help please, What does effective dialogue do for a narrative? Can someone please help me I really need help please help me thank you which expression defies the arithmetic series 10 + 7 + 4 ... for six terms? Another question please if your not busy Given that P(B|A)=0.88 and P(A)=0.46, what is P(B AND A)? Round to three decimal places. Consider the system of equations.y = 3x + 2y=-fx-4Explain why these particular equations can be graphedimmediately 5. Find the vertex and length of the latus rectum for the parabola. Helppp!!!! please!!! Suppose the following regression equation was generated from the sample data of 50 cities relating number of cigarette packs sold per 1000 residents in one week to tax in dollars on one pack of cigarettes and if smoking is allowed in bars: PACKS i= 57221.431732 1423.696906TAXi + 155.441784BARSi + ei. BARS i= 1 if city i allows smoking in bars and BARSi = 0 if city i does not allow smoking in bars. This equation has an R2 value of 0.351292, and the coefficient of BARSi has a P-value of 0.086529. Which of the following conclusions is valid?A. According to the regression equation, regardless of whether or not smoking is allowed in bars, the number of cigarette packs sold per 1000 people decreases by approximately 1424 for each additional dollar of cigarette tax. B. There is evidence at the 0.05 level of significance to support the claim that cities with a smoking ban have lower cigarette sales than those without a smoking ban. C. According to the regression equation, cities that allow smoking in bars have lower cigarette sales than cities that do not allow smoking in bars. D. According to the regression equation, cities that allow smoking in bars sell approximately 155 fewer packs of cigarettes per 1000 people than cities that do not allow smoking in bars. Which fact best supports the city planner's opinion? Designated bike lanes have reduced traffic-related accidents by 43 percent in other cities. A nearby city's business district has bike lanes and a much higher population of commuters. The cost of roadwork in the region has reduced the cost of similar projects by more than 12 percent. Research has proven that bike commuters are healthier and happier than car commuters.