A ceiling fan is turned on and reaches an angular speed of 120 rev/min in 20 s. It is then turned off and coasts to a stop in an additional 40 s. In the one minute of rotation, through how many revolutions did the fan turn?.

Answers

Answer 1

Hi there!

We can first find the angular displacement of the first 20 seconds by finding the angular acceleration.

Begin by converting 120 rev/min to rev/sec:

120 rev/min × 1 min/60 sec = 2 rev/sec

ω = αt

2 = 20α

α = 0.1 rev/sec²

θ = ωit + 1/2αt²

The fan starts from rest, so:

θ = 1/2αt²

θ = 1/2(0.1)(20²) = 20 revolutions

Now, for the next 40 seconds, we can find the fan's deceleration:

ωf = ωi + αt

0 = 2 + αt

-2 = 40α

α = -0.05 rad/sec²

Use the above equation:

θ = ωit + 1/2αt²

θ = 2(40) + 1/2(-0.05)(40²) = 80 - 40 = 40 rev

θ = 4800 - 2400 = 2400 revolutions

Add the two:

θtotal = 20 + 40 = 60 revolutions


Related Questions

Question 5: A heavy rope is flicked upwards, creating a single pulse in the rope. Make a drawing of the rope and indicate the following in your drawing
a. the direction of motion of the pulse
b. Amplitude
c. Pulse length
d. Position of the rest​

Answers

Answer:

the direction of motion of the pulse

How do you find the magnitude of the air inside a balloon?

Answers

Answer:

This demonstration is often done following a discussion of the ideal gas equation of state, PV=nRT.

We begin by weighing a balloon, then blowing it up and weighing it again. In the photo shown on right, the mass indication increased from 3.4 to 3.5 grams. At this point, it is important to note that the scale measures force, even though it reports a conclusion about mass based on the force measurement.

One assumption made in reaching the conclusion is that the buoyant force on the object being weighed is negligible. In the case of the balloon, this is incorrect. The buoyant force on this balloon is equal to the weight of the air displaced.

Since the volume of air inside the balloon is essentially the same as the volume of air displaced, we should expect that the buoyant force would support the weight of the air inside the balloon: The reported mass should not go up at all, because the force required of the scale should not change.

The increase in reported mass of .1 gram is attributed to the higher density of the air inside the balloon: The tension in the balloon compresses the air inside, as attested by the pressure required to blow the balloon up. Evidently, for this experiment, the pressure inside is greater than atmospheric by about 2%.

In the picture at right, the balloon is being pressed into a pan of liquid nitrogen. (The pan is the styrofoam lid of a small lunch box.) The balloon floats lightly on the liquid nitrogen unless pressed down. Pressing down places more surface area in contact with the cold nitrogen and speeds the demonstration. It is interesting to note the buoyant force by this liquified constituent of air.

The balloon shrinks dramatically, as indicated below. When left in contact with the liquid nitrogen long enough (perhaps 5 minutes) the oxygen inside the balloon liquifies, and then the nitrogen liquefies also. Close observation of the photo at the upper left corner of the pan shows some liquid nitrogen bubbles may forming above the dark spot in the center of the pan. One can also make out a faint line at the upper left corner of the pan which is the liquid nitrogen surface. The balloon still floats, riding rather high on that surface. Evidently, some of the balloon contents remain in the gas phase, making the mass of the balloon less than the mass of the displaced liquid nitrogen.

 

Next, we take the shrunken balloon and place it back on the scale, as above. In this instance, the reported mass is 8.7 grams, an increase of 5.2 grams.

A look at the figure on the right shows a faint line near the bottom of the cold balloon. Above that line, the balloon contains gas; below the liquid. That line represents the top surface of the liquid air inside the balloon. With this evidence, the easy thing to say would be, "Of course, liquids are heavier than gases," but that would be incorrect. We assert that the amount of air inside the balloon has not changed and that the mass of that air is not dependent on temperature.

If these assertions are true, then the force of gravity on the balloon has not changed. The scale reading is determined by the force which it must exert on the balloon in order to keep it stationary. Evidently, the required force is larger when the balloon is shrunken. The reason is that the buoyant force (upward) has decreased to practically zero, leaving the scale alone to balance the downward force by gravity.

From the data, we can say that the change in the buoyant force is equal to the weight associated with the apparent change in mass. The weight of 5.2 grams is about .052 newtons. The buoyant force is less now because the balloon displaces less air. If we could measure the change in volume of the balloon as DV, then the buoyant force would be (r g DV) upwards, where r is the density of air that was displaced by the balloon, and g is the gravitational field strength, 9.8 Newton/kg.

Note that the .052 newton force is not the weight of the air inside the balloon. Rather, it is the weight of the air that was displaced by the balloon. If we ignore the compression of air inside the balloon, the two numbers are the same. However, the two samples are completely different.

We can estimate the volume of the balloon by assuming that the hand in the photograph is about .1meters across. For purposes of estimation, we say that the volume shrank to almost zero when the balloon was cold so that the change in volume was nearly equal to the original volume. Plugging in numbers gives fair agreement with the book value of 1kg/cubic meter for the density of air.

The value for the density of air is secondary to two main features of this demonstration:

Large changes in temperature produce the large changes in volume that are indicated by the ideal gas equation.

The mass of air in a volume equal to the volume of a balloon can be determined provided that the buoyant force is understood.

the second law of thermodynamics imposes what limit on the efficiency of a heat engine?

Answers

A heat engine cannot have a thermal efficiency of 100% For all reversible processes, the second-law efficiency is 100%. The second-law efficiency of a heat engine cannot be greater than its thermal efficiency. The second-law efficiency of a process is 100% if no entropy is generated during that process

What is the potential energy of a 50kg car on top of a 600m hill?

Answers

Answer:

294,000 J

Explanation:

The potential energy of a body can be found by using the formula

PE = mgh

where

m is the mass

h is the height

g is the acceleration due to gravity which is 9.8 m/s²

From the question we have

PE = 50 × 9.8 × 600 = 294,000

We have the final answer as

294,000 J

Hope this helps you

the following can increase the amount of friction in the surface, except ______.
a. glue
b. paper
c. lubricant
d. foil​

Answers

Answer:

c. lubricant..........

What is the force that counteracts the thrust force for flight?

Answers

The force which counteracts the thrust force for the flight is known as the drag force, as it opposes the flow.

What is drag force?

Drag is a force that opposes an object's relative motion to a fluid environment in the field of fluid dynamics. It may be among two liquid film (or surfaces) or in between a liquid and a flat wall. The drag force is influenced by velocity, as opposed to other resistive forces like dry contact, which are essentially independent of it.

When a flow is moving at low or high speed, the drag force is equal to the speed for low pressure and to the square of the velocity for high-speed flow. Although viscous friction is what ultimately causes drag, turbulent drag is unaffected by viscosity.

A force in physics is an input that has the power to change an object's motion. A mass-containing object's velocity can vary, or accelerate, as a result of a force. Intuitively, a push or a pull can also be used to describe forces.

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The drag force, which resists the flow, is the force that balances the propulsion force for flight.

What is Drag force?

In the study of fluid dynamics, drag is a force that opposes an object's relative motion to a fluid environment. It could be situated between two liquid surfaces (or films) or between a liquid and a flat wall.

Unlike other resistive forces like dry contact, which are largely independent of velocity, the drag force is affected by it.

For low pressure and high speed flows, respectively, the drag force is equal to the speed for low pressure and the square of the velocity. Although drag is ultimately caused by viscous friction, turbulent.

Thus, The drag force, which resists the flow, is the force that balances the propulsion force for flight.

Learn more about Drag force, refer to the link:

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Question 2 (1 point)
Potential energy depends on...

Speed and velocity

Position or shape

Length and color

Density and volume​

Answers

Answer:

potential energy depends on position or shape

Balanced forces are forces that have equal amount of ________. (word choices: force, repel, attract, motion)

Answers

Answer:

a

Explanation:

if forces on an object are balanced a moving object continues to move at the same speed and in the same direction

How would the gravity between two objects change if one object got bigger?

Answers

The correct answer is the 3rd answer, gravity would increase its pull on the small object

hope this helps! :)

Explain when acceleration remains constant.​

Answers

Explanation:

acceleration remains constant when velocity does not increase or decrease


4. According to Newton's First Law of Motion, an object with a net force acting on it will

Answers

Answer:

a object with net force on it will stay in motion unless acted on by an equal opposite force.

stay in motion unless acted on with another object in motion

2. In a race, if a runner starts and stops at the same position, what is their
displacement? *

Answers

Answer:

It is the same

Explanation:

I Jsut know

1 =
Q=240c
t=300s

Please explain Im so confused

Answers

Answer:

Answer:

0.8 A

Explanation:

Given: Q = 240 C

t = 300 s

Required: I

Equation: I = Q / t

Solution: I = 240 C / 300 s

Answer: I = 0.8 A

a ball is thrown with a speed of 100 m/s at a height of 150 m take g equals 9.8 m per second calculate the time of flight,angle of projection,range pls help I don't know how to solve it​

Answers

Hi there!

Since the ball is thrown with an initial HORIZONTAL velocity, we can treat this as a free-fall situation since the horizontal motion does NOT impact the ball's vertical motion.

We can use the derived kinematic equation:

[tex]t = \sqrt{\frac{2h}{g}}[/tex]

Plug in the given values:

[tex]t = \sqrt{\frac{2(150)}{9.8}} = \large\boxed{5.53 s}}[/tex]

The angle of projection is 0° because there is no vertical component to the velocity as the initial velocity is purely horizontal.

Range:

We can use the equation:

dₓ = vₓt

displacement (x direction) = velocity (x direction) · time

Used the solved-for time and given velocity:

dₓ = 100 · 5.53 = 553 m

Three of the forces in nature attract particles together, with varying strengths, to build the universe. Which is the only one that energizes the universe by making nuclear fusion possible

Answers

Answer:

The photon or quantum of light

Explanation:

Menciona tres diferencias entre un planeta y un satélite natural.

Answers

Answer:

1. Un planeta gira alrededor del Sol mientras que un satélite  gira alrededor de un planeta.

2. Tamaño

3. Aspectos Físicos

4. Creación

En el siguiente circuito se conectan tres resistencias, cuyos valores son: 2 Ω, 3 Ω y 5 Ω. ¿Cuál es el valor de la resistencia total en el circuito? y ¿A qué tipo de circuito corresponde la imagen?

Answers

Answer:

Oh wow, that's a long answer. I don't know what voltage is on the circuit.

the ground wire on a household circuit is typically what color

Answers

Answer:

Hey mate....

Explanation:

This is ur answer.....

Green & Yellow

Hope it helps!

Brainliest pls!

Follow me! :)

The ground wire on a household circuit is green in color in a typical household

What is an electric charge?

Charged material experiences a force when it is subjected to an electromagnetic field due to the physical property of electric charge. You can have positive or negative electric charges (commonly carried by protons and electrons respectively). opposing charges attract one another whereas similar charges repel one another. We refer to an object as neutral if it has no net charge.

The charge on one electron is -1.6 ×10⁻¹⁹ coulomb.

The ground wire is either bare or has green insulation in most residential branch circuit cables in the US.

The norm in Europe and the UK is

live, brown

neutral is blue.

stripes with green and yellow: earth.

Thus,the ground wire on a household circuit is green in color in a typical household

Learn more about an electric charge from here

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A black disk rotates with constant speed and a coin that is located on the edge of the disk moves with speed v. If on a white disk that also rotates with constant speed, we place the same coin on the edge, it is moving with speed 4v. Which disk has a larger radius?

Answers

The white disk has a larger radius.

We know that the speed of the coin v = rω where r = radius of the disk and ω = angular speed of the disk.

Now, since both disks rotate at constant speed, ω = constant.

So, v ∝ r

For the black disk, its radius is r, the coins speed is v.

For the white disk, let its radius be R, the coins rotates at a speed V = 4v

We know that v ∝ r.

Since the coin on the white disk has a greater speed, so its radius would be greater.

So, the white disk has a larger radius.

Learn more about radius of a disk here:

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If a person is pushing a cart with a force of 40 Newtons and it
accelerates at 0.5 m/s², what is the mass of the cart?

Answers

Answer:

80kg

Explanation:

A = Fm

0.5 = 40m

m = 40/0.5

m = 80kg

help please please please please​

Answers

Answer:

lol can u tell what to help u with. cause I didn't understood

solve for the BMI weight 58kg Height 1.61​

Answers

Answer:

Explanation:

BMI= weight/(height × height)          ; weight in kilogram and height in metter

     = 58kg / (1.61m  × 1.61m )

     = (58/ 2.5921) kg/[tex]m^{2}[/tex]

     = 22.375  kg/[tex]m^{2}[/tex]

     ≈ 22.4 kg/[tex]m^{2}[/tex]

Find the gravitational potential energy of a body of mass 25kg,kept at a height of 4m

Answers

Answer:

Massm=2.5kg

Massm=2.5kgGravitational potential energy is the work done against force of gravity is stored in the body at a height h .

Massm=2.5kgGravitational potential energy is the work done against force of gravity is stored in the body at a height h .P.E.=U=mgh

Massm=2.5kgGravitational potential energy is the work done against force of gravity is stored in the body at a height h .P.E.=U=mghU=2.5×10×15

Massm=2.5kgGravitational potential energy is the work done against force of gravity is stored in the body at a height h .P.E.=U=mghU=2.5×10×15U=25/10×10×=375j

A student has fallen behind on her homework and suddenly realizes that a big research paper is due the next day and she has not even started working on it. She panics, staying up all night to write her paper, but still runs out of time. At the last minute, she finds a research paper online that covers the same topic as her paper, and she copies and pastes large portions of text from the website into her paper. The student’s behavior is an example of what? a violation of intellectual property rights an online invasion of privacy inappropriate use of Internet sites an incident of cyberbullying

Answers

Answer:

Violation of intellectual property rights

Explanation:

Im sorry I am late but for the future people its A! :)) Have a great day :)

if there is a gravitational force between all objects, why do we not feel or observe it?

Answers

We do not feel the gravitational forces from objects other than the Earth because they are weak.

Answer:

We do. It's just way too small compared to the force between the objects we're observing and the earth. It's like looking inside a room with an elephant and a grain of rice. The rice is there, it's just too small compared to the room and the elephant inside for you to notice it. Or, if you ever traveled on a plane, you can easily see the towns, or the roads, but not the single people walking the street.

An object has an acceleration of 6.0 m/s/s. If the NetForce was tripled and the mass was halved, then the new acceleration would be _____ m/s/s

Answers

Hi there!

We know that:

∑F = ma

If you tripled the net force and halved the mass:

3F = 1/2ma

Rearrange for 'a':

3F × 2 = ma

6F = ma

Thus, the new acceleration would be 6 times the original, or 36 m/s².

What is the vertical component of a ball thrown at a 27 degree angle at 16 m/s?

Answers

y = y 0 + v 0 y t − 1 2 g t 2 . If we take the initial position y 0 to be zero, then the final position is y = 10 m. The initial vertical velocity is the vertical component of the initial velocity: v 0 y = v 0 sin θ 0 = ( 30.0 m / s ) sin 45 ° = 21.2 m / s .

OK I have tried answering this for a while but im not very good at this so, how many waves will pass in 1 second if it has a frequency of 10 Hz?

Answers

Frequency means waves passing per second. So 10Hz means 10 waves passing a second

If the velocity is 50 and the time is 5 seconds what is the acceleration?

Answers

Just divide the both, you will get the answer!

does it sound rude?

im sorry for that!

Answer:

10

Explanation:

when two waves in the same medium hit each other, the resulting displacement of the medium is

Answers

Explanation:

The resulting displacement of the medium during complete overlap is -1 unit. This is still destructive interference since the two interfering pulses have opposite displacements.

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