2. a) A disc rotates about its axis at speed 25 revolutions per minute and takes 15 s to stop. Calculate the
i) angular acceleration of the disc.
ii) number of rotation of the dise makes before it stops. ​

Answers

Answer 1

The statement shows a case of rotational motion, in which the disc decelerates at constant rate.

i) The angular acceleration of the disc ([tex]\alpha[/tex]), in revolutions per square second, is found by the following kinematic formula:

[tex]\alpha = \frac{\omega_{f}-\omega_{o}}{t}[/tex] (1)

Where:

[tex]\omega_{o}[/tex] - Initial angular speed, in revolutions per second.[tex]\omega_{f}[/tex] - Final angular speed, in revolutions per second. [tex]t[/tex] - Time, in seconds.

If we know that [tex]\omega_{o} = \frac{5}{12}\,\frac{rev}{s}[/tex], [tex]\omega_{f} = 0\,\frac{rev}{s}[/tex] y [tex]t = 15\,s[/tex], then the angular acceleration of the disc is:

[tex]\alpha = \frac{0\,\frac{rev}{s}-\frac{5}{12}\,\frac{rev}{s}}{15\,s}[/tex]

[tex]\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}[/tex]

The angular acceleration of the disc is [tex]\frac{1}{36}[/tex] radians per square second.

ii) The number of rotations that the disk makes before it stops ([tex]\Delta \theta[/tex]), in revolutions, is determined by the following formula:

[tex]\Delta \theta = \frac{\omega_{f}^{2}-\omega_{o}^{2}}{2\cdot \alpha}[/tex] (2)

If we know that [tex]\omega_{o} = \frac{5}{12}\,\frac{rev}{s}[/tex], [tex]\omega_{f} = 0\,\frac{rev}{s}[/tex] y [tex]\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}[/tex], then the number of rotations done by the disc is:

[tex]\Delta \theta = 3.125\,rev[/tex]

The disc makes 3.125 revolutions before it stops.

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Related Questions

If Brad drives 100 meters forwards and then 100 meters backwards, what is her
distance? Her displacement?

Answers

Answer:

0 because she went to exact same place as before

Evaluate tan(249).
O A. 1.36
B. 0.45
C. 0.41
D. 0.91

Answers

Answer:

tan 249 = 2.61

tan 249 = tan (249 - 180) = tan 69 = 2.61

What landforms are found on the Moon? (Select all that apply.)
mountains
plateaus
lakes
craters

Answers

Answer: I think it’s craters

Explanation:

Answer:

MOUNTAINS

CRATERS

PLATEAUS

Explanation:

The Moon has many familiar landforms like mountains, plains, and dark patches that look like seas. We now know that these areas are not seas filled with water. They are deep dry plains.

A stimulus that increses the occurance of a response is called

Answers

Answer:

reinforcing stimulus

Explanation:

Think its correct

Answer:

reinforcing stimulus

Explanation:

because it increases the occurence of a response

Which of the following statements is true?
a Penicillin is produced by fungal fermentation.
b
The effects of too much beer or wine can be
countered with antibiotics.
с
The deadly Death Cap mushroom can be treated
with penicillin.
d Antibiotics do not treat fungal diseases.

Answers

Answer:

a Penicillin is produced by fungal fermentation.

Explanation:

The industrial production of penicillin (PEN) occurs via fermentation using the filamentous fungus Penicillium chrysogenum

Penicillin G (benzylpenicillin) was first produced from a penicillium fungus that occurs in nature. The strain of fungus used today for the manufacture of penicillin G was created by genetic engineering to improve the yield in the manufacturing process.

.5A and 4.5V what’s the resistance

Answers

Explanation:

[tex]V = IR \Rightarrow R = \dfrac{V}{I}[/tex]

Plugging in the numbers, we get

[tex]R=\dfrac{4.5\:\text{V}}{0.5\:\text{A}} = 9.0[/tex] ohms

What is sustainability? How can we make sustainable development a reality? How sustainability can be measured?​

Answers

Answer:

1)The ability to be maintained at a certain rate or amount is called sustainability.

3)Sustainability is measured by assessing performance of Social, Environmental, and Economic principles.

sorry but I don't know number 2.

I hope it will help you)):

help pls will give brainiest :)

Answers

Answer:

use a flight sim

A 500 kg car is at rest at the top of a 72 m high hill. The car rolls to the bottom of the hill. At the bottom of the hill, the car has a speed of 25.6 m/s. Calculate the mechanical energy of the car at the top and bottom of the hill. (Assume the bottom of the hill has a height of 0 m, g=9.80 ms2/).

Answers

Explanation: Solution

1.

Gravitational potential energy

U=mgh=500*9.8*50

U=245000 J

2.

Kinetic energy is present at bottom of the hill

K=(1/2)mV2=(1/2)*500*27.82

K=193210 J

3.

Work done by friction

W=193210-245000=-51790 J

The mechanical energy at the top and bottom of the hill is equal to 352800 J and 163840 J respectively.

What is the kinetic energy and potential energy?

Kinetic energy (KE) can be described as the energy possessed by a moving object due to its motion. Work by a body will be done to change the kinetic energy. The kinetic energy is represented as K.E = ½mv².

Potential energy (P.E) can be described as the energy that is stored by an object due to its position and is represented in the equation as P.E = mgh, where ‘m’ is the mass, ‘g’ is the acceleration due to gravity and ‘h’ is the height.

The mechanical energy = Kinetic energy + potential energy

Given, the mass of the car, m = 500 Kg

The height of the hill, h = 72 m

The velocity of the car, v = 25.6 m/s

At the top of the hill, the mechanical energy = potential energy

The potential energy at the top of the hill, = mgh

P. E. = 500 × 9.8 ×72

P.E. = 352800 J

At the bottom of the hill, the mechanical energy = kinetic energy

The kinetic energy of the car at the bottom of the hill,

K.E. =  ½ × 500 (25.6)²

K.E. = 163840 J

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Car A uses tires for which the coefficient of static friction is 0.384 on a particular unbanked curve. The maximum speed at which the car can negotiate this curve is 16.7 m/s. Car B uses tires for which the coefficient of static friction is 0.809 on the same curve. What is the maximum speed at which car B can negotiate the curve

Answers

Car C would like a summary too

What is the kinetic energy of a 36N toy car which is moving at 5 m/s?

Answers

Correct option is
C
y
max

=11 m
Work done =mgh

2
1

×base×height=mgh
(area under the curve is work done)

2
1

×11×100=5×10×h

or h=11m

You have a new goal of saving at least $4,500 over the course of the next year.

You already have $900 saved.

By how much would you need to increase your monthly net savings in order to meet this goal?

Answers

Answer:

You would need to save $300 every month to meet your savings goal.

Explanation:

4,500-900=3,600

3,600/12=300

Answer:

answer is 200

Explanation:

edge 2021

How do you explain this arrangement of fossils? What might have happened?

Answers

Answer:

The question lacks a photo to fully answer correctly

If the fossil has its neck bent backwards towards its back, that is the common way to which dinosaurs died.

If the fossil is scattered a bit from its other linking fossil pieces, than it is most likely that the dinosaur was a meal to a predator.

Fossils that are in array but are divided clearly at a section suggests that land moved. Possibly earthquake or Pangea took place.

Answer:

Peripatus, which lived around 570 MYA, is in the top layer of rock. The trilobites that lived later, between 498 MYA and 445 MYA, appear in the bottom layer. Based on superposition, younger layers of rock are expected to be on top. The rock layers have been overturned, placing the younger layer on the bottom.

Explanation:

actually answer plauto

A student is asked to calculate the centripetal acceleration of a hummingbird that makes a complete circle in 0.43 seconds. If the circle has a radius of 0.25 m, what is
the correct setup for determining the centripetal acceleration of the hummingbird?
(3.65m/s)2/0.25m
(3.65m/s)2-0.43
O (0.435)2 / 25m
O (0.432.25m

Answers

The centripetal acceleration of the hummingbird is [tex]\frac{(3.65)^2}{0.25} = 53.29 \ m/s^2[/tex]

The given parameters;

time of motion of the hummingbird, t = 0.43 sradius of the circle, r = 0.25 mnumber of revolution of the hummingbird = 1 rev per 0.43 s

The angular speed of the hummingbird is calculated as follows;

[tex]\omega = \frac{1 \ rev}{0.43 \ s} \times \frac{2\pi \ rad}{1 \ rev} =14.61 \ rad/s[/tex]

The linear speed of the hummingbird is calculated as follows;

v = ωr

v = 14.61 x 0.25

v = 3.65 m/s

The centripetal acceleration of the hummingbird is calculated as follows;

[tex]a_c = \frac{v^2}{r} \\\\a_c = \frac{(3.65)^2}{0.25} \\\\a_c = 53.29\ m/s^2[/tex]

Thus, the centripetal acceleration of the hummingbird is [tex]\frac{(3.65)^2}{0.25} = 53.29 \ m/s^2[/tex]

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real answers only pls

Answers

Answer:

1. it spins

2. falls in a curve

3. falls flat on the floor

A rock falls to the ground with a force of 300N and air resistance pushes back up on the rock with a
force of 45N. Which is true of the rock?
A There are balanced forces acting on the rock and the net force is 255N down
B. There are unbalanced forces acting on the rock and the net force is 255N down
C. There are balanced forces acting on the rock and the net force is 345N down
. There are unbalanced forces acting on the rock and the net force is 345N down

Answers

Answer:

c

Explanation:

Which term describes energy stored in the bonds between atoms?
A. Nuclear energy
B. Chemical energy
O C. Thermal energy
D. Sound energy

Answers

Answer:

B. Chemical energy

Explanation:

chemical energy is the energy stored in the bonds between atoms

HELP!!! I HAVE NO IDEA!!!!!!!!!!!!!

1. A rocket has a mass of 0.8 kg and an engine that provides 100 N of force. A second rocket is being designed to use the same engine but accelerate at half the rate of the first rocket. What is the mass of the second rocket?

a. 0.4 kg
b. 1.6 kg
c. 2.4 kg
d. 0.8 kg


2. Which of the following would be a situation with unbalanced forces?

a. Two people pulling on the same side of a wheelbarrow
b. A team of players in tug of war pulling on the rope, each team with equal numbers of people pulling with equal strength
c. Two people of opposite sides of a big tire. One pushes the tire and one pulls it with equal force
d. Two people not touching a crate that is sitting stationary.


3. Why is it generally easier to push a heavy object that is already moving instead of the same heavy object that is stationary

a. The force of gravity on the object is different if it is stationary or not.
b. The force of friction on the object is different if it is stationary or not
c. The force of the push on the object is different if it is stationary or not
d. The normal force on the object is different if it is stationary or not.

Thanks In Advance!! (I will mark brainliest) :)

Answers

Answer:

Explanation:

The engine should create the same force

1) F = ma

  F = M(½a)

therefore

ma = ½Ma

 m = ½M

 M = 2m

 M = 2(0.8)

 M = 1.6 kg

2) Unbalanced forces

 a. Two people pulling on the same side of a wheelbarrow

 c. Two people of opposite sides of a big tire. One pushes the tire and one pulls it with equal force

3) b. The force of friction on the object is different if it is stationary or not

A 20 kg box rests on the ground. Round all answers to the hundredths, if necessary. What is the weight of the box?​

Answers

Mass=m=20kgAcceleration due to gravity=10m/s^2

Weight=Applied force

[tex]\\ \sf\longmapsto F=mg[/tex]

[tex]\\ \sf\longmapsto F=20(10)[/tex]

[tex]\\ \sf\longmapsto F=200N[/tex]

Answer:

Weight=200

Explanation:

Given,

[tex]\sf\longmapsto \: mass = 20 \: kilograms[/tex]

We know that–

[tex]\sf\longmapsto \: acceleration \: \: because \: of \: gravity = 10m/s^2[/tex]

[tex]\sf\longmapsto \: Weight= \: is  \: F = m•g[/tex]

Let's start solving!

Weight = 20×10

Weight=200

How does our body get heat ? Explain in short .
For class 5 plz bro i need help​

Answers

Answer:

Thermogenesis:Your body's muscles, organs, and brain produce heat in a variety of ways

Explanation:

For example, muscles can produce heat by shivering. Hormonal thermogenesis: Your thyroid gland releases hormones to increase your metabolism. This increases the energy your body creates and the amount of heat it produces

a matter can be separated into which of the following choices​

Answers

A matter can be separated into three states.

SolidLiquidGasIn solid state the bonding between atoms is maximum.In liquid state the bonding between atoms is less than solid.In gaseous state the bonding between atoms is minimum
1. solid
2. liquid
3. gas

CAN SOMEBODY PLEASE HELP ME?!?!?!??!??!?!?!?!

Answers

Answer:

B. The force of gravity that acts on the kitten

Explanation:

Starting at 9a.m., you ride your hover board for 3hrs at an average speed of 6 mph. Out of breath, you stop for tea from noon until 2p.m. What is your average speed over the interval from 9a.m. to 2p.m.?

Answers

3 times 6= 18. The average speed is 19 mph.

hope this helps!

What process makes this pattern on the ocean floor?

Answers

Plate tectonics


and the ocean floor
Bathymetry, the shape of the ocean floor, is largely a result of a process called plate tectonics.

please give me brainliest

How long does it take light from a camera to travel to the face of someone standing 7 meters away?

Answers

The time taken for the light to travel from the camera to someone standing 7 m away is 2.33×10¯⁸ s

Speed is simply defined as the distance travelled per unit time. Mathematically, it is expressed as:

Speed = distance / time

With the above formula, we can obtain the time taken for the light to travel from the camera to someone standing 7 m away. This can be obtained as follow:

Distance = 7 m

Speed of light = 3×10⁸ m/s

Time =?

Time = Distance / speed

Time = 7 / 3×10⁸

Time = 2.33×10¯⁸ s

Therefore, the time taken for the light to travel from the camera to someone standing 7 m away is 2.33×10¯⁸ s

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Content from magnets

Answers

Answer:

magnets are magnetic :)

Explanation:

ALREADY SOLVED Thank you for looking.

Answers

what nonsense you are say it have been solved when why did you put

Answer:

yes

Explanation:

helphelphelp due in 5 minutes answer the question below

Answers

The correct answer is B

A person on a bike (m = 90 kg) is traveling 4 m/s at the top of a 2 m hill. What is the biker's total energy?

a) 1,944 J

b) 2,484 J

c) 1,764 J

d) 720 J

Answers

Answer:

Explanation:

Total mechanical energy is

E = mgh + ½mv²

E = m(gh + ½v²)

E = 90(9.8(2.0) + ½4²)

E = 2,484 J answer b)

A person on a bike (m = 90 kg) is traveling 4 m/s at the top of a 2 m hill. the total energy of the biker would be 2484 Joules.

What is mechanical energy?

Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total potential energy stored energy in the system which is represented by total potential energy.

As given in the problem a person on a bike (m = 90 kg) is traveling 4 m/s at the top of a 2 m hill.

The total kinetic energy of the biker

KE = 1/2 × m × v²

    = 0.5 × 90 × 4²

    = 720

Similarly, the total potential energy of the biker

PE = m × g × h

     =90 × 9.8 × 2

      = 1764 Joules

The total energy of the biker = 720 + 1764

                                                 = 2484 Joules

Thus, the total energy of the biker would be 2484 Joules .

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Verificar
El gráfico de la velocidad de una bola que rueda por un canal se muestra en la
figura:

a) La velocidad de la bola luego de 5 s.
0.6m/s
b) La distancia recorrida en el intervalo t : (0-5) s
1.5m
c) La distancia recorrida en el intervalo t: (5-10) s
3m
d) La aceleración de la bola en el intervalo t: (10-12) s.
-0.4m/s^2
e) La distancia total recorrida.
6.9m
f) La rapidez media de la bola
0.58m/s

Answers

El análisis de un grafico de velocidad versus tiempo permite encontrar los resultados para las preguntas son:

a) La velocidad es v= 0,6 m/s

b) La distancia recorrida  dₐ = 1,5 m

c) La distancia recorrida entre t= 5 y 10 s es  [tex]d_b[/tex] = 3,0 m

d) La aceleración   a = -0,4 m/s²

e) La distancia total recorrida  es [tex]d_{total}[/tex] = 5,3 m

f) La velocidad media es  [tex]v_{media}[/tex] = 0,44 m/s

La cinemática estudia el movimiento de los cuerpos, buscando relaciones entre la posición, la velocidad y la aceleración de los cuerpos.

La velocidad es definida como el cambio de la posición en función del tiempo y la aceleración es el cambio de la velocidad en el intervalo de tiempo.

           .[tex]v= \frac{\Delta x}{t} \\a = \frac{\Delta v}{t}[/tex]

           

Donde v y a son la velocidad y aceleración, respectivamente, t es el tiempo y Δx y Δv son la variación de la posición y la velocidad, respectivamente.  

En el adjunto muestran un grafico de la velocidad en función del tiempo, donde del área bajo la curva obtenemos la distancia recorrida y la pendiente corresponde a la aceleración del cuerpo.

Respondamos las preguntas:

a)  La velocidad de la bola a los 5 s.

Como es un grafico de velocidad versus tiempo, la velocidad puede ser leída directamente, en el grafico tenemos un valor de

          v= 0,6 m/s  

b) La distancia recorrida corresponde al área bajo la curva.

         [tex]d_a = \frac{v_f - v_o}{2} t \\d_a = \frac{0.6-0}{ 2}\ 5[/tex]  

         d = 1,5 m

c) La distancia en el intervalo de 5 a 10 s.

En este intervalo la velocidad es constante, el área es

        [tex]d_b = v \Delta t\\d_b = 0.6 \ 5\\[/tex]  

        d =  3 m

d) La aceleración en el intervalo  10 a 12 s.

         

La aceleracion es la pendiente del grafico

        a = [tex]\frac{\Delta v}{\Delta t}[/tex]  

        a = [tex]\frac{-0.2 - 0.6}{12-10}[/tex]

        a = -0,4 m/s²

El signo negativo indica que la aceleración se opone a la velocidad del cuerpo.

e) La distancia total recorrida  

       [tex]d_{total} = d_a + d_b + d_c[/tex]

      dₐ = 1,5 m

      [tex]d_b[/tex] = 3,0 m

Busquemos la distancia en el ultimo intervalo

         [tex]d_c = \frac{0.6 + 0.2}{2} ( 12-10)[/tex]

       [tex]d_c[/tex] = 0,8 m

Substituimos

     [tex]d_{total}[/tex] = 1,5 + 3,0 + 0,8

     [tex]d_{total}[/tex]  =  5,3 m

f) La rapidez  de la bola

     

La rapidez prmedio es la relación entre la distancia recorrida en el tiempo.

         [tex]v_{avg} = \frac{\Delta x}{\Delta t }[/tex]  

         [tex]v_{avg} = \frac{5.3}{12}[/tex]

         [tex]v_{avg}[/tex]  =0,44 m/s

En conclusión usando el análisis de un grafico de velocidad versus tiempo podemos encontrar los resultados para las preguntas son:

         a) La velocidad es v= 0,6 m/s

         b) La distancia recorrida  da = 1,5 m

         c) La distancia recorrida entre t= 5 y 10 s es  db = 3,0 m

         d) La aceleración   a = -0,4 m/s²

         e)  La distancia total recorrida  es [tex]d_{total}[/tex] = 5,3 m

          f) La velocidad media es  [tex]v_{avg}[/tex] = 0,44 m/s

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