5/6 When switched on, the grinding machine accelerates from rest to its operating speed of 3450 rev/min in 6 seconds. When switched off, it coasts to rest in 32 seconds. Determine the number of revolutions turned during both the startup and shutdown periods. Also determine the number of revolutions turned during the first half of each period. Assume uniform angular acceleration in both cases.

Answers

Answer 1

Answer:

Δθ₁ =  172.5 rev

Δθ₁h =  43.1 rev

Δθ₂ =   920 rev

Δθ₂h = 690 rev

Explanation:

Assuming uniform angular acceleration, we can use the following kinematic equation in order to find the total angle rotated during the acceleration process, from rest to its operating speed:

       [tex]\Delta \theta = \frac{1}{2} *\alpha *(\Delta t)^{2} (1)[/tex]  

Now, we need first to find the value of  the angular acceleration, that we can get from the following expression:

       [tex]\omega_{f1} = \omega_{o} + \alpha * \Delta t (2)[/tex]

Since the machine starts from rest, ω₀ = 0.We know the value of ωf₁ (the operating speed) in rev/min.Due to the time is expressed in seconds, it is suitable to convert rev/min to rev/sec, as follows:

       [tex]3450 \frac{rev}{min} * \frac{1 min}{60s} = 57.5 rev/sec (3)[/tex]

Replacing by the givens in (2):

       [tex]57.5 rev/sec = 0 + \alpha * 6 s (4)[/tex]

Solving for α:

       [tex]\alpha = \frac{\omega_{f1}}{\Delta t} = \frac{57.5 rev/sec}{6 sec} = 9.6 rev/sec2 (5)[/tex]

Replacing (5) and Δt in (1), we get:

       [tex]\Delta \theta_{1} = \frac{1}{2} *\alpha *(\Delta t)^{2} = \frac{1}{2} * 6.9 rev/sec2* 36 sec2 = 172.5 rev (6)[/tex]

in order to get the number of revolutions during the first half of this period, we need just to replace Δt in (6) by Δt/2, as follows:

       [tex]\Delta \theta_{1h} = \frac{1}{2} *\alpha *(\Delta t/2)^{2} = \frac{1}{2} * 6.9 rev/sec2* 9 sec2 = 43.2 rev (7)[/tex]

In order to get the number of revolutions rotated during the deceleration period, assuming constant deceleration, we can use the following kinematic equation:

       [tex]\Delta \theta = \omega_{o} * \Delta t + \frac{1}{2} *\alpha *(\Delta t)^{2} (8)[/tex]

First of all, we need to find the value of the angular acceleration during the second period.We can use again (2) replacing by the givens:ωf =0 (the machine finally comes to an stop) ω₀ = ωf₁ = 57.5 rev/secΔt = 32 s

       [tex]0 = 57.5 rev/sec + \alpha * 32 s (9)[/tex]

Solving for α in (9), we get:

       [tex]\alpha_{2} =- \frac{\omega_{f1}}{\Delta t} = \frac{-57.5 rev/sec}{32 sec} = -1.8 rev/sec2 (10)[/tex]

Now, we can replace the values of ω₀, Δt and α₂ in (8), as follows:

        [tex]\Delta \theta_{2} = (57.5 rev/sec*32) s -\frac{1}{2} * 1.8 rev/sec2\alpha *(32s)^{2} = 920 rev (11)[/tex]

In order to get finally the number of revolutions rotated during the first half of the second period, we need just to replace 32 s by 16 s, as follows:[tex]\Delta \theta_{2h} = (57.5 rev/sec*16 s) -\frac{1}{2} * 1.8 rev/sec2\alpha *(16s)^{2} = 690 rev (12)[/tex]

Related Questions

PLEASE I NEED HELP CLICK ON THIS IMAGE

Answers

I believe you are incorrect. A weathered mountain would appear more jagged.

I do believe with a lot of exposure to weather will make the mountain appear somewhat more jagged compared to a mountain that is less weathered.

If this is incorrect, please, don't refrain to tell me.

Which of the following is necessary in order to classify the different types of
electromagnetic radiation?

Answers

Answer:

The EM spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The common designations are: radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.

Explanation:

HOPE THIS HELPS! ;)

In order to classify the different types of electromagnetic radiation, frequency is necessary.

What is electromagnetic radiation?

The EM spectrum have seven different regions in terms of decreasing wavelength. The increase in energy and frequency denotes decreasing wavelength. The parts of EM spectrum are radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.

Thus, in order to classify the different types of electromagnetic radiation, frequency is necessary.

Learn more about electromagnetic spectrum.

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A pendulum is made up of a small sphere of mass 0.500 kg attached to a string of length 0.950 m. The sphere is swinging back and forth between point A, where the string is at the maximum angle of 35.0∘ to the left of vertical, and point C, where the string is at the maximum angle of 35.0∘ to the right of vertical. The string is vertical when the sphere is at point B. Calculate how much work the force of gravity does on the sphere from A to B.

Answers

Answer:

W = 0.842 J

Explanation:

To solve this exercise we can use the relationship between work and kinetic energy

         W = ΔK

In this case the kinetic energy at point A is zero since the system is stopped

         W = K_f                (1)

now let's use conservation of energy

starting point. Highest point A

          Em₀ = U = m g h

Final point. Lowest point B

         Em_f = K = ½ m v²

energy is conserved

         Em₀ = Em_f

         mg h = K

to find the height let's use trigonometry

at point A

            cos 35 = x / L

            x = L cos 35

so at the height is

            h = L - L cos 35

            h = L (1-cos 35)

we substitute

           K = m g L (1 -cos 35)

we substitute in equation 1

           W = m g L (1 -cos 35)

let's calculate

           W = 0.500 9.8 0.950 (1 - cos 35)

           W = 0.842 J

7. Copper can be coated on the surface of iron but not on silver? why​

Answers

Answer:

Silver has greater electronegativity (pull on electrons) than copper, so it will be reduced rather than oxidized. Silver ions will plate out on copper metal. Sir the coating of iron with copper surface can be referred as IRON-COPPER PLATING.

Explanation:

Iron is used for the electroplating of so copper because iron falls above copper in the electrochemical series whereas silver will fall off below the copper in electrochemical series that makes it not reliable for the electroplating purpose

state three factors that determine the strength of electromagnetic​

Answers

Answer:

Factors that affect the strength of electromagnets are the nature of the core material, strength of the current passing through the core, the number of turns of wire on the core and the shape and size of the core.Nov 28, 2020

Explanation:

the number of turns of wire on the core and the shape and size of the core.

3) A rather large fish is about to eat an unsuspecting small fish. The big fish has a mass of 5kg and is
swimming at 8 m/s, while the small fish has a mass of 1 kg and is swimming at -4 m/s. What is the
velocity of big fish after lunch?

Answers

Answer:

the velocity of the big fish after the launch is 6 m/s.

Explanation:

Given;

mass of the big fish, m₁ = 5 kg

velocity of the big fish, u₁ = 8 m/s

mass of the small fish, m₂ = 1 kg

velocity of the small fish, u₂ = -4 m/s

Let the final velocity of the big fish after launch = v

Apply the principle of conservation linear momentum;

m₁u₁ + m₂u₂ = v(m₁ + m₂)

5 x 8   + 1 x (-4) = v(5 + 1)

40 - 4 = 6v

36 = 6v

v = 36/6

v =  6 m/s.

Therefore, the velocity of the big fish after the launch is 6 m/s.

A cyclist traveling at 5m/s uniformly accelerates up to 10 m/s in 2 seconds. Each tire of the bike has a 35 cm radius, and a small pebble is caught in the tread of one of them. (A) What is the angular acceleration of the pebble during those two seconds

Answers

Answer:

[tex]a=2.5\ m/s^2[/tex]

Explanation:

Given that,

Initial speed, u = 5 m/s

Final speed, v = 10 m/s

Time, t = 2 s

The radius of the tire of the bike, r = 35 cm

We need to find the angular acceleration of the pebble during those two seconds. It can be calculated as follows.

[tex]a=\dfrac{v-u}t{}\\\\a=\dfrac{10-5}{2}\\\\a=2.5\ m/s^2[/tex]

So, the required angular acceleration of the pebble is equal to [tex]2.5\ m/s^2[/tex].

a forward horizontal force of 50 N is applied to crate a second horizontal force of 180 N is applied to crate in the opposite direction determine the magnitude and direction of the resultant force acting on the crate

Answers

Answer:

130n on the 2nd horizontal

Explanation:

HELP a lot of points and brainliest Step 3: Measure the Speed of the Toy Car on the Lower Track
Calculate the change in time for each quarter of the track. Record the change in time in Table C of your Student Guide.

The change in time for the first quarter is
seconds.

The change in time for the second quarter is
seconds.

The change in time for the third quarter is
seconds.

The change in time for the fourth quarter is
seconds.

Answers

Answer:

is that 4 question each one of them we have to solve

A straight wire, labeled as Wire A, lies horizontally on a tabletop and is oriented to run north-south. A conventional current of 1.0 amperes runs in the wire directed towards the north. A second wire, labeled as Wire B, is also laid on the tabletop oriented north- south. Which of the following statements is true?

a. If Wire B carries no current in it and lies to the left (west) of wire A, then it will experience an attractive force to the right towards wire A).
b. If Wire B carries a northward conventional current and lies to the left (west) of wire A, then it will experience an attractive force to the right (towards Wire A).
c. If Wire B carries a northward conventional current and lies to the right (east) of wire A, then it will experience a repulsive force to the right (away from Wire A).
d. If Wire B carries a southward conventional current and lies to the left (west) of wire A, then it will experience a repulsive force to the left (away from Wire A).

Answers

Answer:

b. If Wire B carries a northward conventional current and lies to the left (west) of wire A, then it will experience an attractive force to the right (towards Wire A).

d. If Wire B carries a southward conventional current and lies to the left (west) of wire A, then it will experience a repulsive force to the left (away from Wire A).

Explanation:

Two parallel conductors experience attractive force when the current flowing in the conductors are in the same direction.

Also two parallel conductors experience repulsive force when the current flowing in the conductors are in opposite direction.

Therefore, b and d are the correct options.

b. If Wire B carries a northward conventional current and lies to the left (west) of wire A, then it will experience an attractive force to the right (towards Wire A).

d. If Wire B carries a southward conventional current and lies to the left (west) of wire A, then it will experience a repulsive force to the left (away from Wire A).

The motor of a washing machine rotates with a period of 28 ms. What is the angular speed, in units of rad/s?

Answers

Answer:

2π/[28 x (10^-3)]

Explanation:

Angular speed : ω=2π/T

T = 28ms = 28 x (10^-3) s

Angular speed = 2π/[28 x (10^-3)]

Betty hits a baseball.
At which point along the baseball's path does it have the most gravitational potential energy?

Answers

Answer:

point 2

Explanation:

Define threshing?

Brainliest For the right answer​

Answers

Answer:

Process used for separating grains from the stalks is known as threshing, In this process, stalks are beaten to free the grain seeds.

Answer:

Threshing is extraction of wheat germ from the stalk. In today's usage the combine tractor cuts and threshes the wheat at the same time. Imagine a big lawn mower with a rotating drum inside.

The drum turns and shakes the germ out of the wheat, the seeds falling through small holes onto a conveyor belt one way, the leftover grass dumping out the other way. The grain is poured into a truck driving beside the combine.

In old times, grain had to be beaten out of the grass on a Threshing Floor.

PLEASE I NEED HELP CLICK ON THIS IMAGE

Answers

answer: A
explanation: the definition of weathering is:
the breaking down of rocks,soils, and minerals

Rewire each of the following using the correct prefix using 2 decimal places where applicable.
a.0.00000123N
b. 417 000 000 kg
c. 246800
d. 0,00088 mm​

Answers

Answer:

a. 1.2×10^-6

b. 0.42×10^9

c. 246.8×10^3

d. 88

2. An object is dropped from rest. Calculate its velocity after 2.5s if it is dropped:
a.On Earth, where the acceleration due to gravity is 9.8m/s?
b. On Mars, where the acceleration due to gravity is 3.8m/s?

Answers

Answer:

a=24.5 b=9.5

Explanation:

What are the two main processes carried out by the excretory system?​

Answers

water and carbon dioxide

Which of the following relationships is correct?
2 points
1 N = 1 kg
1 N = 1 kg·m
1 N = 1 kg·m/s
1 N = 1 kg·m/s2

Answers

1 N = 1 kg•m is the answer

effect of high pitch on humans​

Answers

Answer:

High frequency sound causes two types of health effects: on the one hand objective health effects such as hearing loss (in case of protracted exposure) and on the other hand subjective effects which may already occur after a few minutes: headache, tinnitus, fatigue, dizziness and nausea.

How do you find the period of a sound wave?

Answers

Answer:

Period refers to the time for something to happen and is measured in seconds/cycle. In this case, there are 11 seconds per 33 vibrational cycles. Thus the period is (11 s) / (33 cycles) = 0.33 seconds. We now know that the period is 3.2 seconds and that the frequency is 0.31 Hz.

A 60 kg swimmer at a water park enters a pool using a 2 m high slide. Find the velocity of the swimmer
at the bottom of the slide.

Answers

Answer:

the velocity of the swimmer at the bottom of the slide is 6.26 m/s

Explanation:

The computation of the velocity of the swimmer at the bottom of the slide is given below:

v = √2gh

= √2 × 9.8 × 2

= 6.26 m/s

Hence, the velocity of the swimmer at the bottom of the slide is 6.26 m/s

The velocity of the swimmer at the bottom of the slide will be 6.26 m/s.The pace of displacement change  with reference to time is referred to as the velocity

What is velocity?

The change of displacement with respect to time is defined as the velocity. Velocity is a vector quantity. it is a time-based component. Velocity at any angle is resolved to get its component of x and y-direction.

The velocity is found as;

[tex]\rm v= \sqrt{2gh} \\\\ \rm v= \sqrt{2\times 9.81 \times 2}\\\\ \rm v= 6.26 \ m/sec[/tex]

Hence velocity of the swimmer at the bottom of the slide will be 6.26 m/s.

To learn more about the velocity refer to the link ;

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Fill in the graph for 50 points

Answers

Answer:

Speed: 3, 4, 5, 6. Distance: 1, 2, 3, 4, 5

Answer:

Speed: 3, 4, 5, 6. Distance: 1, 2, 3, 4, 5

Explanation:

g Suppose you have this brilliant idea: A Ferris wheel has radial metallic spokes between the hub and the circular rim (of radius roughly 16 m). These spokes move in the magnetic field of the Earth (5e-05 T), so each spoke acts like a rotating bar in a magnetic field. The magnetic field points perpendicular to the plane of the Ferris wheel. You plan to use the emf generated by the rotation of the Ferris wheel to power the light-bulbs on the wheel. Suppose the period of rotation for the Ferris wheel is 90 seconds. What is the magnitude of the induced emf between the hub and the rim

Answers

Answer:

[tex]4.46\times 10^{-4}\ \text{V}[/tex]

Explanation:

B = Magnetic field = [tex]5\times 10^{-5}\ \text{T}[/tex]

r = Radius of rim = 16 m

t = Time = 90 seconds

A = Area of rim = [tex]\pi r^2[/tex]

EMF is given by

[tex]\varepsilon=\dfrac{BA}{t}\\\Rightarrow \varepsilon=\dfrac{5\times 10^{-5}\times \pi\times 16^2}{90}\\\Rightarrow \varepsilon=0.000446=4.46\times 10^{-4}\ \text{V}[/tex]

The magnitude of the induced emf between the hub and the rim is [tex]4.46\times 10^{-4}\ \text{V}[/tex].

A consumer uses 3098 kWh in 29 days. The utility company charges AED 0.077592 per kWh for the electricity plus AED 0.029998 per kWh for the distribution of the electricity . What is the consumer's electric bill for the 29 days?

Answers

for the electricity, multiply 0.077592 by 3098 and you get 240.380016.
for the distribution, multiply 0.029998 by 3098 and you get 92.933804.

you add those two numbers (240.380016 + 92.933804) for the total in 29 days and you get 297.31382 AED

The consumer electric bill for 29 days is AED 331.31

Given that, The utility company charges AED 0.077592 per kWh for the electricity plus AED 0.029998 per kWh for the distribution of the electricity

Since, A consumer uses 3098 kWh in 29 days.

The  utility company charges for electricity is,

                                  [tex]=0.077592*3098=240.38[/tex]

The  utility company charges for distribution of the electricity  is,

                                  [tex]=0.029998*3098=92.93[/tex]

So that, The consumer electric bill is,

                         [tex]=240.38+92.93=333.31[/tex]

Hence, the consumer electric bill for 29 days is AED 331.31

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Exact solutions for gravitational problems involving more than two bodies are notoriously difficult. One solvable problem involves a configuration of three equal-mass objects spaced in an equilateral triangle. Forces due to their mutual gravitation cause the configuration to rotate. Suppose three identical stars, each of mass M, form a triangle of side L. Find an expression for the period of their orbital motion.

Answers

Answer:

  T = [tex]4\pi ^2 \ \sqrt{ \frac{L^3}{GM} }[/tex]

Explanation:

Let's analyze the situation, as the stars have the same mass and all are at the same distance, the magnitude of the force is constant, even when its direction changes, Let's use Newton's second law

             F = m a

in this case the force is the universal attraction

             F = G M₁ M₂ / r²

they relate it is centripetal

             a = v² / r = w² r

we substitute

             G M² / r² = M w² r

              w² = [tex]\frac{G M}{r^3}[/tex]

angular velocity is related to frequency and period

              w = 2π f = 2π / T

     

we substitute

              [tex](\frac{2\pi }{T })^2 = \frac{G M}{r^3}[/tex]

              T = [tex]4\pi^2 \ \sqrt{ \frac{r^3}{G M}}[/tex]

in this case  r= L

             T = [tex]4\pi ^2 \ \sqrt{ \frac{L^3}{GM} }[/tex]

An optical disk drive in your computer can spin a disk up to 10,000 rpm (about 1045 rad/s1045 rad/s ). If a particular disk is spun at 734.1 rad/s 734.1 rad/s while it is being read, and then is allowed to come to rest over 0.569 seconds0.569 seconds , what is the magnitude of the average angular acceleration of the disk

Answers

Answer:

[tex]1290.16\ \text{rad/s}^2[/tex]

Explanation:

[tex]\omega_i[/tex] = Initial angular velocity = 734.1 rad/s

[tex]\omega_f[/tex] = Final angular velocity = 0

t = Time = 0.569 seconds

[tex]\alpha[/tex] = Angular acceleration

From the kinematic equations of rotational motion we have

[tex]\omega_f=\omega_i+\alpha t\\\Rightarrow \alpha=\dfrac{\omega_f-\omega_i}{t}\\\Rightarrow \alpha=\dfrac{0-734.1}{0.569}\\\Rightarrow \alpha=-1290.16\ \text{rad/s}^2[/tex]

The magnitude of the average angular acceleration of the disk is [tex]1290.16\ \text{rad/s}^2[/tex].

The phrase that best describes a field is:

a tower of power
a source of momentum
a sphere of influence
a lever arm

Answers

a sphere of influence no?

Answer:

a sphere of influence mmmmmmmmmmm not actually right

Which term does this explain?
This is a non-mathematical explanation of how nature works. It must be
supported by a large body of evidence.
Fact
Law
Theory
Hypothesis

Answers

It is a fact because I just want to post a question man so I have to answers something pp poop

Transcranial magnetic stimulation (TMS) is a noninvasive technique used to stimulate regions of the human brain. A small coil is placed on the scalp, and a brief burst of current in the coil produces a rapidly changing magnetic field inside the brain. The induced emf can be sufficient to stimulate neuronal activity. One such device generates a magnetic field within the brain that rises from zero to 1.2 T in 100 ms. Determine the magnitude of the induced emf within a circle of tissue of radius 1.3 mm and that is perpendicular to the direction of the field.

Answers

poste en français s’il vous plaît

Suppose that you changed the area of the bottom surface of the friction cart without changing its mass, by replacing the Teflon slab with one that was smaller but thicker. The contact area would shrink, but the normal force would be the same as before. Would this change the friction force on the sliding cart

Answers

Answer:

in this case the weight of the vehicle does not change , consequently the friction force should not change

Explanation:

The friction force is a macroscopic manifestation of the interactions of the molecules between the two surfaces, this force in the case of solid is expressed by the relation

          fr = μ N

          W-N= 0

          N = W

as in this case the weight of the vehicle does not change nor does the Normal one, consequently the friction force should not change

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