F?=75N,F?=40N,F?=75N,F?=90N.

A dvd drive has a maximum speed of 72000 revolutions per minute. if a dvd has a diamter of 12 what is the linear speed

Brilliant_brown [7]

The question isn't clear enough, I think it ask us to calculate the linear speed of a point at the edge of the DVD.
Now let's imagine we're a point at the edge of the DVD, we're undergoing a circular motion. Each minute we will complete a circular track 7200 times, now we need to know the distance we travel each turn. The perimeter of the DVD, a circular object is:
$P=2\pi.R$
Know recall that:
$v=\frac{d}{t}$
We now need to know how much distance is traveled during a minute or 60 seconds:
$D=7200\times 2\pi\times R$
Finally we divide this result with t=60 seconds:
$v=\frac{7200\times2\pi\times R}{60}
\\
R=\frac{12}{2}=6
$
$v\approx 4523.89 \frac{units}{second}$
Where the distance units were named units as the length unit is not specified in this exercise.

7 0

4 years ago

Light rays in a material with index of refrection 1.29 1.29 can undergo total internal reflection when they strike the interface

deff fn [24]

Answer:

The second material's index of refraction is 1.17.

Explanation:

Given that,

Refractive index of the material, n = 1.29

Critical angle is 65.9 degrees.

We need to find the second material's index of refraction. We know that at critical angle of incidence, angle of refraction is equal to 90 degrees. Using Snell's law as:

$n_1\sin \theta_c=n_2\sin (90)\\\\n_2=n_1\sin \theta_c\\\\n_2=1.29\times \sin (65.9)\\\\n_2=1.17$

So, the second material's index of refraction is 1.17.

7 0

3 years ago

Wanda and Marita are drinking bottles of water. Each girl sounds a different musical note by blowing across the top of her bottl

sesenic [268]

If there is less water in the bottle then the note played is lower, because there is more air to move around. This is one good hypothesis that could lead to a new experiment.

Hope that helps! ★ If you have further questions about this question or need more help, feel free to comment below or post another question and send the link to me. -UnicornFudge aka Qamar

5 0

3 years ago

Read 2 more answers

A comet orbits a star in a strongly elliptical orbit. The comet and star are far from other massive objects. As the comet travel

Kruka [31]

Answer:

the kinetic energy decreases and the potential energy Increases.

Explanation:

as the comet travels away from the star it gains an energy which it posses because of its position or state.once the comet moves away form the star the kinetic decreases until its lost all together to where the potential energy starts increasing.

3 0

3 years ago

Read 2 more answers

if the vessel in the sample problem accelerates fir 1.00 min, what will its speed be after that minute ?

LUCKY_DIMON [66]

Answers:

a) 154.08 m/s=554.68 km/h

b) 108 m/s=388.8 km/h

Explanation:

The complete question is written below:

In 1977 off the coast of Australia, the fastest speed by a vessel on the water was achieved. If this vessel were to undergo an average acceleration of $1.80 m/s^{2}$ , it would go from rest to its top speed in 85.6 s.

a) What was the speed of the vessel?

b) If the vessel in the sample problem accelerates for 1.00 min, what will its speed be after that minute?

Calculate the answers in both meters per second and kilometers per hour

a) The average acceleration $a_{av}$ is expressed as:

$a_{av}=\frac{\Delta V}{\Delta t}=\frac{V-V_{o}}{\Delta t}$ (1)

Where:

$a_{av}=1.80 m/s^{2}$

$\Delta V$ is the variation of velocity in a given time $\Delta t$ , which is the difference between the final velocity $V$ and the initial velocity $V_{o}=0$ (because it starts from rest).