Answer:
shown in the attachment
Explanation:
The detailed step by step and necessary mathematical application is as shown in the attachment.
A centrifuge accelerates uniformly from rest to 15000 rpm in 330 s . Through how many revolutions did it turn in this time?
1 answer:
Answer:
The number of revolutions turned by the centrifuge is 8250 revolutions.
Explanation:
Given;
number of revolution per minutes, ω = 15000 rpm
time of motion, t = 330 s = 5.5 minutes
The number of revolutions turned by the centrifuge is given by;
Therefore, the number of revolutions turned by the centrifuge is 8250 revolutions.
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First of all we need to convert everything into SI units.
Let's start with the initial angular speed,
. Keeping in mind that
we have
And we should also convert the angle covered by the centrifuge:
This is the angle covered by the centrifuge before it stops, so its final angular speed is
.
To solve the problem we can use the equivalent of
of an uniformly accelerated motion but for a rotational motion. It will be
And by substituting the numbers, we can find the value of
, the angular acceleration:
Let's start with the initial angular speed,
we have
And we should also convert the angle covered by the centrifuge:
This is the angle covered by the centrifuge before it stops, so its final angular speed is
To solve the problem we can use the equivalent of
of an uniformly accelerated motion but for a rotational motion. It will be
And by substituting the numbers, we can find the value of
Answer:
775.48 W
Explanation:
given,
diameter of disk = 0.6 cm
length of the disk = 0.4 m
T₁ = 450 K T₂ = 450 K T₃ = 300 K
= 1.33
now,
the value of view factor (F₁₂)corresponding to 1.33
F₁₂ = 0.265
F₁₃ = 1 - 0.265 = 0.735
now,
net rate of radiation heat transfer from the disk to the environment:
= 2 F₁₃ A₁ σ (T₁⁴ - T₃⁴)
= 2 x 0.735 x π x (0.3)² x (5.67 x 10⁻⁸ W/m²) (450⁴ - 300⁴)
= 775.48 W
Net radiation heat transfer from the disks to the environment = 775.48 W
