Why rolling friction less than sliding friction

Answers

Answer 1

The force of friction depends on the area of contact between the two surfaces. As the area of contact is less in the case of rolling than in the case of sliding that's why rolling friction is less than the sliding friction. More the contact area more the friction.


Related Questions

If a man travels from 0m to 5m then back to -3m, all in four seconds, what is the mans displacement?

Answers

Answer:

-3 m

Explanation:

Displacement is the final position minus the initial position.

Δx = x − x₀

Δx = -3 m − 0 m

Δx = -3 m

1. Which statement about friction is true?(1 point) A. Static friction and kinetic friction in a system always act in the same direction as each other and in the opposite direction of the applied force. B. Static friction and kinetic friction in a system always act in the same direction as each other and in the same direction as the applied force. C. Static friction and kinetic friction in a system always act in opposite directions of each other and in the same direction as the applied force. D. Static friction and kinetic friction in a system always act in opposite directions of each other and in the opposite direction of the applied force. 2. A brick is resting on a smooth wooden board that is at a 30° angle. What is one way to overcome the static friction that is holding the brick in place?(1 point) A. roughen up the texture of the wooden board B. press down on the brick in a direction that is perpendicular to the board C. lower the board so it's level with the ground D. raise the board to a higher angle

Answers

Answer:

true 1Ay 2D

Explanation:

1) In this exercise you are asked to investigate which statements are true

A) True. The friction force opposes the movement caused by the external force,

B) False. Mantuano in the opposite direction force

C) False. The static and scientific friction force act in the same direction, since the second appears when the movement does not start and the static friction decreases.

D) Fale the static and kinetic friction forces act in the same direction

2) How to overcome friction on a ramp

A) False. If the texture of the surface becomes rough, the friction force increases

B) False. Pressing the brick against the surface increases the normal and as the friction is proportional to the normal, it also increases

C) False. By lowering the table the weight component in the friction direction decreases

D) True. When lifting the board, the weight component increases and therefore can become greater than the friction

          Wx-fr = ma

           W sin tea - my mg cos tea = m a

As it increases, the sine increases and the cosine decreases.

Imagina que compras una placa rectangular de metal de 2mm de alto, 10mm de ancho x 50mm de largo, y una masa de 0.02kg. El vendedor te dice que es de oro, pero para ver si de verdad es de oro, lo verificas calculando la densidad de la placa. ¿Cuál es el valor de la densidad de la placa? ¿Es de oro la placa rectangular?

Answers

Answer:

Densidad de la placa = 20 g/cm³.

La placa no es de oro.

Explanation:

Para encontrar la densidad de la placa rectangular primero debemos hallar su volumen:

[tex] V = 2 mm*10 mm*50 mm = 1000 mm^{3}*\frac{1 cm^{3}}{(10 mm)^{3}} = 1 cm^{3} [/tex]      

Ahora, encontremos al densidad de la placa:

[tex] d = \frac{m}{V} = \frac{20 g}{1 cm^{3}} = 20 g/cm^{3} [/tex]

Dado que la densidad del oro es 19.32 g/cm³ y que la densidad de la placa rectangular calculada es 20 g/cm³, podemos decir que dicha placa no es de oro.                  

Espero que te sea de utilidad!

An internal combustion engine has an efficiency of 22.3%. This engine is used to deliver 6.25 x 104 J of work to drive the motion of the train. What is the total energy that needs to be put into the engine.

Answers

Answer:

Only about 12%–30% of the energy from the fuel you put in a conventional vehicle is used to move it down the road, depending on the drive cycle. The rest of the energy is lost to engine and driveline inefficiencies or used to power accessories. Therefore, the potential to improve fuel efficiency with advanced technologies is enormous.

Buildings are more dense than the surrounding air. This means that they have more _____ per volume than the air and will stay on the ground instead of floating up into the atmosphere.

Answers

Answer:

mass

Explanation:

Density is the measure of how much mass of a substance is squeezed into a given volume of that substance. It is the mass per unit volume, and substances with lesser density will float in materials with denser density. Buildings are generally more obviously denser that air, if not we'll see then float upwards into the atmosphere, but that is not the case. Different liquids too can separate and form layers on one another due to their differences in volume.

A car is traveling at 50 m/s and slows down to 10 m/s in 5 seconds. What is
the car's acceleration? (Remember what is needed when an object slows
down) *

Answers

Answer:

-8m/s2

Explanation:

it decelerate. initial velocity u=50m/s and final velocity v= 10m/s and the time t= 5s

using this equation v= u+at

a= v-u/t= 10-50/5=-40/5= -8m/s2

Answer:

[tex] \boxed{\sf Acceleration \ (a) = -8 \ m/s^2} [/tex]

Given:

Initial velocity (u) = 50 m/s

Final velocity (v) = 10 m/s

Time taken (t) = 5 seconds

To Find:

Acceleration (a) of the car

Explanation:

From equation of motion we have:

[tex] \boxed{ \bold{v = u + at}}[/tex]

By substituting value of v, u & t in the equation we get:

[tex] \sf \implies 10 = 50 + 5a \\ \\ \sf \implies 5a + 50 = 10 \\ \\ \sf \implies 5a = 10 - 50 \\ \\ \sf \implies 5a = - 40 \\ \\ \sf \implies a = - \frac{40}{5} \\ \\ \sf \implies a = - 8 \: m {s}^{ - 2} [/tex]

[tex] \therefore[/tex]

Acceleration (a) of the car = -8 m/s²

An electric iron of resistance 20Ω takes a current of 5A. Calculate the heat developed in 30seconds?

Answers

ANSWER:-

The amount of heat (H) produced is given by the joule’s law of heating as H= Vlt

Where,

Current, I = 5 A

Time, t = 30 s

Voltage, V = Current x Resistance = 5 x 20 = 100V

H= 100 x 5 x 30 = 1.5 x 10⁴ J.

Therefore, the amount of heat developed in the electric iron is 1.5 x 10⁴J.

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As a 1850 kg car is traveling down a road, it experiences a force of friction of 121 N and a force of air resistance if 186N. If the engine is not applying any force, what is the acceleration of the car

Answers

Answer:

  -0.166 m/s²

Explanation:

F = Ma

a = F/M = (121 N +186 N)/(1850 kg) = 0.166 m/s²

The acceleration of 0.166 m/s² is in the direction opposite to the direction of travel, so might be considered to be negative.

Answer:

 -0.166 m/s²            

As a 1850 kg car is traveling down a road, it experiences a force of friction of 121 N and a force of air resistance if 186N. If the engine is not applying any force, what is the acceleration of the car

5. a) A boy used a catapult to pluck a mango from a tree. State two forces involved in this activity?​

Answers

Explanation:

Tensional force and gravitational force

The _______ is responsible for absorbing the most UV radiation.
a.
troposphere
b.
stratosphere
c.
mesosphere
d.
thermosphere


Please select the best answer from the choices provided

A
B
C
D

Answers

Answer:

The stratosphere is responsible for absorbing the most UV radiation.

Explanation:

Hope it will help you:)

The Stratosphere is responsible for absorbing the most UV radiation.

What is Stratosphere?The stratosphere is the second layer of the atmosphere as you go upward lying between the troposphere and the mesosphere.The external temperature of these planes decreases and then increases as they leave the stratosphere and return to the ground.This increase in temperature is a result of the ozone layer that is present in the stratosphere and absorbs the UV rays from the Sun, making an elevation in temperature.  The stratosphere layer also called the ozonic atmospheric envelope, is important to human's life as it contains the ozone layer which absorbs the harmful ultraviolet radiations which emitted from the Sun and also it is convenient for flying of the planes .

Thus, the Stratosphere is responsible for absorbing the most UV radiation.

Hence, Option B is the correct answer.

Learn more about Stratosphere,

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A voltage source is connected across two 1 kohm resistors in parallel. The current flowing through the voltage source is measure by a current meter as 2 mA. What is the voltage across each resistor

Answers

Answer:

1 Volt

Explanation:

The resistors have resistance R = 1 kΩ each = 1 x 10^3 Ω each

The current through the voltage source I= 2 mA = 2 x 10^-3 A

The resistors are in parallel, son the total resistance will be

[tex]\frac{1}{R_{T}}[/tex] = [tex]\frac{1}{R_{1}} + \frac{1}{R_{2}}[/tex]

[tex]\frac{1}{R_{T}}[/tex] = 1/1 kΩ  + 1/1 kΩ

[tex]\frac{1}{R_{T}}[/tex]  = 2/1 kΩ

[tex]R_{T}[/tex] = 1 kΩ ÷ 2 = 0.5 kΩ = 500 Ω

From V = IR

where V is the voltage

I is the current

R is the resistance

substituting, we have

V = 500 x 2 x 10^-3 = 1 V   This is the voltage across each resistor

If a · b = 20, a = 4, and the angle between the vectors a and b is 30°, what is the magnitude of vector b? Incorrect: Your answer is incorrect.

Answers

Answer:

The magnitude of [tex]\vec b[/tex] is approximately 5.774.

Explanation:

According to the definition of dot product:

[tex]\vec a\bullet \vec b = \|\vec a \|\cdot \|\vec b\|\cdot \cos \theta[/tex]

Where:

[tex]\|\vec a\|[/tex], [tex]\|\vec b\|[/tex] - Norms (or magnitudes) of [tex]\vec a[/tex] and [tex]\vec b[/tex], dimensionless.

[tex]\theta[/tex] - Internal angle between [tex]\vec a[/tex] and [tex]\vec b[/tex], measured in sexagesimal degrees.

The magnitude of [tex]\vec b[/tex] is therefore cleared:

[tex]\|\vec b\| = \frac{\vec a \bullet \vec b}{\|\vec a\|\cdot \cos \theta}[/tex]

Given that [tex]\vec a \bullet \vec b = 20[/tex], [tex]\|\vec a\| = 4[/tex] and [tex]\theta = 30^{\circ}[/tex], the magnitude of [tex]\vec b[/tex] is:

[tex]\|\vec b\| = \frac{20}{4\cdot \cos 30^{\circ}}[/tex]

[tex]\|\vec b\| \approx 5.774[/tex]

The magnitude of [tex]\vec b[/tex] is approximately 5.774.

What is the purpose of a kink in a thermometer?

Answers

Answer:

A 'kink' in the glass tube which breaks the mercury as it contracts, storing the highest temperature reading. The glass tube is shaped like a lens to magnify the thin mercury thread. Shaking the thermometer resets the mercury back into the bulb.

Kink in the Mercury thermometer helps to prevents the falling of mercury present in capillary  tube into bulb. It ensures that the user takes the correct reading of temperature. That's the reason a person before taking a new reading must give a sudden shake to the clinical thermometer so that the mercury level comes to normal .

HELP ME PLS!

Determine the presssure at the bottom of a container filled
with gasoline, if the height of the container is 200 cm long.
The gasoline's density is 680 kg/m3.

Answers

Explanation:

Pressure = Height * Density * acc. due to gravity

P = 2 * 680 * 9.8 = 13, 328 Pa

Answer:

13328pa

Explanation:

p = hgd

h = height = 200cm = 2m

g = 9.8m/s²

d = density = 680kg/m³

p = pressure

p = 2 x 9.8 x 680 = 13328pa

Two students make a model of a tree house they want to
The scale is 1:44. In the scale model, the tree house
has 2 windows.
How many windows should the real tree house have?
O A. 2
O B. 22
C. 4
D. 88

Answers

Answer:

A 2

Explanation:

Scaling deals with measurements.

for example, the question says, 1 : 44. Assuming we're using cm : m, this is inferring that, 1 centimeter on the model will represent 44 meters in real life. This means, the number of windows in the real tree will be carried down to the model, only the sizes would be reduced.

if a window in the real tree measures 44 meters, then it would be scaled down to be 1 centimeter on the model.

irrespective, models doesn't change the number of features, only the dimensions.

What is the momentum of a 950kg car moving at 10.0m/s

Answers

Explanation:

Momentum = mass × velocity

p = mv

p = (950 kg) (10.0 m/s)

p = 9500 kgm/s

Mention any three consequences of gravitational force.

It's Group C question so... :-!​

Answers

Answer:

[tex] \boxed{ \bold{ \sf{see \: below}}}[/tex]

Explanation:

The force with which any two objects attract each other is called gravitational force. Any three consequences of gravitational force are given below :

The existence of the solar family and constellations.The revolution of planets around the sun.Formation of tides in the sea.

Hope I helped!

Best regards!

The gravitational force keeps atmospheric gases available to all living beings, allows the moon to orbit around the earth and the earth to orbit around the sun (causing day and night), and keeps all living beings trapped in the surface of the planet.

Gravity is a fundamental element of nature and can be defined as follows:

It is the element responsible for defining the weight of a body or object.It is responsible for defining the vertical force.It is the force of attraction between two bodies.

Through this, we can conclude that gravity is essential for life on the planet and for the functioning of the universe as a whole. This explains the importance of studying and understanding the gravitational force.

You can find more information about this at the link below:

https://brainly.com/question/9571572?referrer=searchResults

where would information on the chemical and physical properties of a specific chemical be located in a laboratory or in the workplace?

Answers

Answer:

Both

Explanation:

Which sport requires participants to wear safety equipment during competition?

Answers

Answer:

Football

Explanation:

Answer:

Hockey

Explanation:

The answer is hockey because in order to play hockey you have to have a lot of safety equipment because people play hockey by being very close to one another. Also, getting hurt during playing hockey without proper equipment can cause many damages to your body.

Hope this helps! :D

A block of wood measures 12cm x 5cm x 10cm. Calculate the volume in (i) cm3 (ii) m3

Answers

Given:-

A block of wood measures 12cm x 5cm x 10cm.

To be calculated:-

Calculate the volume in (i) cm3 (ii) m3

Solution:-

Case 1 :

Volume of wood = 12cm x 5cm x 10cm

= 600 cm³

Case 2 :

12 cm = 12/100 = 0.12 m

5 cm = 5/100 = 0.05 m

10 cm = 10/100 = 0.01 m

Volume of wood = 0.12 × 0.05 × 0.01

= 0.00006 m³

A 0.40 kg mass hangs on a spring with a spring constant of 12 N/m. The system oscillated with a constant amplitude of 12 cm. What is the maximum acceleration of the system

Answers

Answer:

The maximum acceleration of the system is 359.970 centimeters per square second.

Explanation:

The motion of the mass-spring system is represented by the following formula:

[tex]x(t) = A\cdot \cos (\omega \cdot t + \phi)[/tex]

Where:

[tex]x(t)[/tex] - Position of the mass with respect to the equilibrium position, measured in centimeters.

[tex]A[/tex] - Amplitude of the mass-spring system, measured in centimeters.

[tex]\omega[/tex] - Angular frequency, measured in radians per second.

[tex]t[/tex] - Time, measured in seconds.

[tex]\phi[/tex] - Phase, measured in radians.

The acceleration experimented by the mass is obtained by deriving the position equation twice:

[tex]a (t) = -\omega^{2}\cdot A \cdot \cos (\omega\cdot t + \phi)[/tex]

Where the maximum acceleration of the system is represented by [tex]\omega^{2}\cdot A[/tex].

The natural frequency of the mass-spring system is:

[tex]\omega = \sqrt{\frac{k}{m} }[/tex]

Where:

[tex]k[/tex] - Spring constant, measured in newtons per meter.

[tex]m[/tex] - Mass, measured in kilograms.

If [tex]k = 12\,\frac{N}{m}[/tex] and [tex]m = 0.40\,kg[/tex], the natural frequency is:

[tex]\omega = \sqrt{\frac{12\,\frac{N}{m} }{0.40\,kg} }[/tex]

[tex]\omega \approx 5.477\,\frac{rad}{s}[/tex]

Lastly, the maximum acceleration of the system is:

[tex]a_{max} = \left(5.477\,\frac{rad}{s})^{2}\cdot (12\,cm)[/tex]

[tex]a_{max} = 359.970\,\frac{cm}{s^{2}}[/tex]

The maximum acceleration of the system is 359.970 centimeters per square second.

"the toy car is about 3 inches long"is an example of a ________ observation

Answers

It's a quantitative observation because it includes numerical data.

A car traveling at 30 mis runs out of gas while traveling up a 10o slope. How far up the hill will the car coast before starting to roll back down

Answers

Answer:

5.21 miles

Explanation:

The set up will be a right angle triangle (an inclined plane). The height of the inclined plane is the opposite side of the triangle while the distance traveled by the car along the slope will be the hypotenuse with angle of inclination of 10°.

Using the SOH trigonometry identity i.e sinθ = opposite/hypotenuse

sin 10° = opposite/30

opposite = 30sin10°

opposite = 5.21 miles

Hence the car must have traveled 5.21 miles up the hill before starting to roll back down.

HELP PLEASE !!!!!!! If a ball is accelerating down through the air with no horizontal motion, what must be true about the net forces acting on the ball? The gravitational force is greater than the drag. The net force on the ball is zero. The drag is greater than the gravitational force. The net force on the ball is directed upward.
physics

Answers

Answer:

A. The gravitational force is greater than the drag.

Explanation:

Remember that the second Newton's law says that:

F = m*A

Force equals mass times acceleration.

With this we will see that the correct option is:

"The gravitational force is greater than the drag."

We know that the ball is accelerating downwards, and there is no horizontal motion. Because the acceleration is downwards, we know that the net force must be downwards (for the second law).

Now, what must be true about the net forces acting on the ball? let's analyze each statement:

1) "The gravitational force is greater than the drag."

The gravitational force is what causes the objects to fall down to the ground, so if the ball is falling, this will always be true.

2) " The net force on the ball is zero."

We know that the ball is accelerating, thus the net force can not be zero, this is false.

3) "The drag is greater than the gravitational force. "

This is the opposite to the first option, this is false.

4) "The net force on the ball is directed upward."

The acceleration and the net force have the same direction, if the ball is accelerating downwards, then the net force is directed downwards. This is false.

Then the only true statement is the first one:

"The gravitational force is greater than the drag."

If you want to learn more, you can read:

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You find a micrometer (a tool used to

measure objects to the nearest 0.001 mm) that has

been badly bent. How would it compare to a new,

high-quality meterstick in terms of its precision? Its

accuracy?

Answers

Explanation:

If the micrometer is still in the working condition, it will be hard for the observer to find its accuracy or precision, which could be matched with the meter stick. Its accuracy can be compromised in comparison with the undamaged micrometer, but it would be more chances of highly precise.

The error which is find in the damaged micrometer would be less than as compared to the width of the hash marks on the stick.

Answer:

The bent micrometer will be more precise but less accurate than the meterstick

Explanation:

convert 64,000 cm to m

Answers

Answer:

64,000 centimeters =640 meters

Answer:

640 metres

Explanation:

100 cm = 1 m

1 cm = 1/100 m

64000 cm = 64000 × 1/100 metres

= 640 metres.

HOPE IT HELPS ◉‿◉

An atom of sodium-23 (Na-23) has a net charge of +1. Identify the number of protons, neutrons, and electrons in the atom. Then, explain how you determined the number of each type of particle

Answers

Answer:

11 protons, 12 neutrons, 10 electrons

Explanation:

Sodium has an atomic number of 11, so it has 11 protons.

The atomic mass is 23, so there are 23 − 11 = 12 neutrons.

The charge is +1, so there is 1 more proton than electrons, so there are 10 electrons.

name the three scale of temperature

Answers

Answer:

Three scales of temperature are

Celcius scale

Fahrenheit scale

Kelvin scale

Explanation:

Hope it will help :)

Answer:

Celsius (is the most used)FahrenheitKelvin

Does adding fertilizer affect the growth of a plant

Answers

Answer:

yes it does affect the growth of plants

Fertilizers provide essential nutrients to plants in form of soluble salt compounds, and directly affect plant growth.

A woman dropped a dime in a wishing well , she heard it 30 sec later ..Find velocity on impact while moving at 9.8 m/s 2

Answers

Answer:

The velocity at impact is 222.2 m/s

Explanation:

The given information are;

The time at which the woman heard the sound of the coin after dropping it into the wishing well = 30 seconds

The average speed of sound in air = 344 m/s

The time in which the dime travel = t₁

The time in which the sound travel = t₂

1/2 × 9.8 × t₁² = 344 × t₂

t₁ + t₂ = 30

4.9·t₁² = 344 × (30 - t₁)

4.9·t₁² + 344·t₁ - 10320 = 0

Which gives -344±

[tex]t_1 = \dfrac{-344\pm \sqrt{344^{2}-4\times 4.9 \times 10320}}{2\times 4.9}[/tex]

t₁  = 22.676 seconds or -92.9 seconds

Therefore the correct natural time is t₁  = 22.676 seconds

The velocity at impact, v = g×t₁ = 9.8 × 22.676  = 222.2 m/s

The velocity at impact= 222.2 m/s.

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