A flywheel flows from 250rpm to 150rpm in 4.2 seconds. How many revolutions occur during this time

14 revolutions

Explanation:

Given that,

Initial angular velocity,

Final angular velocity,

Time, t = 4.2 seconds

We need to find the number of revolutions occur durung this time.

250 rpm = 26.17 rad/s

150 rpm = 15.70 rad/s

Let is angular acceleration. Using first equation to find it.

Now let us suppose that the number of revolutions are .

or

Hence, there are 14 revolutions.

The average speed during the slowdown is 200 RPM.

4.2 seconds is (4.2/60) = 0.07 minute.

(200 rev/minute)x(0.07 minute)= 14 revs

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.

i believe the answer would be:

d. violin, clarinet, french horn, and tuba