Ask question

Ask question

All categories

1 year ago

6

In the lab downstairs physics majors use a rotating mirror to measure the speed of light within a few percent of the actual valu

e they switch the mirror from rotating clockwise at 115 rad/s to counter clockwise at 115 rad/s over the course of 85 seconds. Assume constant angular acceleration.
QUESTION: how many revolutions does the rotating mirror go through when it gets to a 0 angular velocity along the way to new speed. SHOW WORKING OUT

1 answer:

iris [78.8K]1 year ago

7 0

The number of complete cycles the rotating mirror goes through before the angular velocity gets to zero is approximately 1166.8 revs

<h3>What is angular velocity?</h3>

Angular velocity is the ratio of the angle turned to the time taken.

The kinematic equation for angular velocity are presented as follows;

ω = ω₀ + α·t

θ = θ₀ + ω₀·t + 0.5·α·t²

Where;

θ₀ = The initial angle turned = 0

ω₀ = The initial angular velocity of the mirrors = 115 rad/s clockwise

α = The angular acceleration = (115 - (-115))rad/s/(85 s) = -46/17 m/s²

t = The duration of the motion;

When the angular velocity, ω is zero, we get;

0 = 115 - 46/17·t

t = 85/2

Which indicates;

θ = 0 + 115× (85/2) + 0.5×(46/17) ×(85/2)² = 7331.25

θ = 7331.25 radians

θ = 7331.25/(2×π) ≈ 1166.8 rev

The mirrors would have turned through approximately 1166.8 revolutions when the angular gets to zero

Learn more about angular velocity and acceleration here:

brainly.com/question/13014974

#SPJ1

You might be interested in

what are two properties that lead to electromagnetic interactions? pls help I'm so confused and cant find the answer anywhere!!

MArishka [77]

Answer:

Electric charge. A fundamental property that leads to the electromagnetic interactions among particles that make up matter.

8 0

3 years ago

1. Clara stops for 10 minutes to catch up with a friend.

lesya692 [45]

Answer:

Clara has speed of 80m/min

Explanation:

Clara was jogging at 600 m in 5 minutes. She stopped suddenly which reduced her velocity and then she waited for 10 minutes so that her friends comes near her. She stopped to catch her friend. During this 10 minutes the velocity of Clara is zero. She started to walk again at a slower speed of 80m/min.

4 0

3 years ago

In 5 meters, a person running at 0.8 m/s accelerates at 1.6 m/s2. How fast 16 points

frutty [35]

They were going at a velocity 4.07m/s

<u>Explanation:</u>

Distance s =5 m

initial velocity u= 0.8 m/s

Acceleration a =1.6m/s2

We have to calculate the velocity with which they were going afterwards i.e final velocity.

Use the equation of motion

$v^2=u^2+2as\\=0.8^2+2\times 1.6\times 5\\=16.64\\v=4.07 m/s$

They were going with a velocity 4.07 m/s afterwards.

5 0

3 years ago

An electron with charge −e and mass m moves in a circular orbit of radius r around a nucleus of charge Ze, where Z is the atomic

shepuryov [24]

Answer:

$v=\sqrt{\frac{kZe^2}{mr}}$

Explanation:

The electrostatic attraction between the nucleus and the electron is given by:

$F=k\frac{(e)(Ze)}{r^2}=k\frac{Ze^2}{r^2}$ (1)

where

k is the Coulomb's constant

Ze is the charge of the nucleus

e is the charge of the electron

r is the distance between the electron and the nucleus

This electrostatic attraction provides the centripetal force that keeps the electron in circular motion, which is given by:

$F=m\frac{v^2}{r}$ (2)

where

m is the mass of the electron

v is the speed of the electron

Combining the two equations (1) and (2), we find

$k\frac{Ze^2}{r^2}=m\frac{v^2}{r}$

And solving for v, we find an expression for the speed of the electron:

$v=\sqrt{\frac{kZe^2}{mr}}$

6 0

3 years ago

When a virus enters a living cell, the virus

sleet_krkn [62]

Answer:

d. causes the cell to make more viruses

Explanation:

Viruses depend on the host cells that they infect to reproduce. When found outside of host cells, viruses exist as a protein coat or capsid, sometimes enclosed within a membrane. The capsid encloses either DNA or RNA which codes for the virus elements.

6 0

3 years ago