When objects are forced to vibrate ( like when dropped onto a hard surface), they will do so at their

A compact disc (CD) stores music in a coded pattern of tiny pits 10⁻⁷m deep. The pits are arranged in a track that spirals outwa

Serggg [28]

a) Angular speed of the innermost part: 50 rad/s, outermost part: 21.6 rad/s

b) The length of the track would be 5,550 m

c) The average angular acceleration is $-6.4\cdot 10^{-3}rad/s$

Explanation:

a)

For an object in uniform circular motion, the relationship between angular speed and linear speed is

$v=\omega r$

where

v is the linear speed

$\omega$ is the angular speed

r is the radius of the circle

Here the linear speed of the track is constant:

v = 1.25 m/s

For the innermost part of the disk,

r = 25.0 mm = 0.025 m

So the angular speed is

$\omega_i = \frac{v}{r_i}=\frac{1.25}{0.025}=50 rad/s$

For the outermost part,

r = 58.0 mm = 0.058 m

So the angular speed is

$\omega_o = \frac{v}{r_o}=\frac{1.25}{0.058}=21.6 rad/s$

b)

The maximum playing time of the disk is

$t=74.0 min \cdot (60 s/min)=4440 s$

If the track was stretched out in a straight line, the motion of the track would be a uniform motion (since it is moving at constant speed), so we can use the equation

$v=dt$

where

v is the linear speed

d is the length coverted in a straight line

t is the time

Substituting v = 1.25 m/s and solving for d,

$d=vt=(1.25)(4440)=5550 m$

c)

The angular acceleration is given by

$\alpha = \frac{\omega_f - \omega_i}{t}$

where

$\omega_f$ is the final angular speed

$\omega_i$ is the initial angular speed

t is the time

A CD is read from the innermost part to the outermost part, so we have:

$\omega_i = 50 rad/s$ (at the innermost part)

$\omega_f = 21.6 rad/s$ (at the outermost part)

t = 74.0 min = 4440 s is the time

Substituting, the average angular acceleration is

$\alpha = \frac{21.6-50.0}{4440}=-6.4\cdot 10^{-3}rad/s$

where the negative sign means the CD is decelerating.

Learn more about circular motion:

brainly.com/question/2562955

brainly.com/question/6372960

#LearnwithBrainly

6 0

2 years ago

A cyclist accelerates from 0m/s to 8m/s in 3 seconds.

garik1379 [7]

Answer:

the rate of acceleration is 2.6666(and so on) if thats your question

Explanation:

5 0

2 years ago

Determine the amount of work done by the applied force when a 87 N force is applied to move a 15 kg object a horizontal

elena-s [515]

Answer:

391.5 J

Explanation:

The amount of work done can be calculated using the formula:

W = F║d
where the force is parallel to the displacement

Looking at the formula, we can see that the mass of the object does not affect the work done on it.

Substitute the force applied and the displacement of the object into the equation.

W = (87 N)(4.5 m)
W = 391.5 J

The amount of work done on the object is 391.5 J in order to move it 4.5 meters with an applied force of 87 Newtons.

5 0

2 years ago

Read 2 more answers

How would improvement in use of renewable energy sources impact climate change sea-level rise?

bonufazy [111]

Answer:

Almost immeasurably small.

Explanation:

The STORY is that humans are BAD for the environment and have caused a HUGE change in the amount of CO₂ in the atmosphere.

Let's look at the reports and draw our own conclusions.

Current CO₂ levels are 409.8 parts per million (PPM)

at the beginning of the Industrial revolution in the 1700's, the presumed beginning of the huge increase in CO₂ the level was about 280 PPM

For perspective lets assume we capture the whole atmosphere and squish it down to 2400 one liter bottles of air

That's 100 cases of 24 bottles per case.

We now separate all the air components into their own bottles

Nitrogen is 78% of our air, so we subtract 78 cases from our 100 leaving 22

Subtracting Oxygen at 21% of air leaves 1 case of liter bottles left

Of those 24 bottles, Argon makes up 0.93% of air so we subtract 22 bottles

The remaining two bottles contain all of the other gasses in our air, One of those bottles contains CO₂.

If we take the CO₂ levels from the 1700's at about 280 PPM as a baseline and assume ALL of the increase is human caused, that is (410 -280) / 280 = 46 % of the total.

The human caused addition of CO₂ would be 460 mililiters out of 2400 liters over the course of 250 years

The claim is, that less than half of a liter of CO₂ out of 2400 liters of air is responsible for heating not only the gas in all the other bottles but also the surface of the earth itself.

Personally, it boggles my mind.

And it says NOTHING of a far more powerful greenhouse gas that is far more prevalent in the atmosphere...water vapor.

Water vapor is about 1% of air at sea level and about 0.4% overall. It was not considered in the above analysis because water vapor can condense out and is not a constant in the air.

Notice that there is about 100 times the amount of water vapor in the air as compared to CO₂. Water vapor also has between 4 and 8 times the greenhouse effect that CO₂ does.

Makes one wonder why we choose to pick on CO₂.

7 0

3 years ago

A crane does 300 Joules of work in 6 seconds. How much power was used?

HACTEHA [7]

Answer: P= mad/t or P=w/t so P= 300/6= 50 W

6 0

2 years ago