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3 years ago

Need help on science please!

Physics

1 answer:

grigory [225]3 years ago

3 0

Fossil fuels are formed when dead, buried, and decomposing organisms are compressed under extreme pressure and heat for millions of years. We need other sources of fuel today... s<span>trictly speaking you don't. But if we hold off developing alternatives until the fossil fuels truly run out, then there will be absolute chaos getting the new ones available. Thats all i got

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An electric motor can drive grinding wheel at two different speeds. When set to high the angular speed is 2000 rpm. The wheel tu

shutvik [7]

a) The initial angular speed is 209.3 m/s

b) The angular acceleration is $-1.74 rad/s^2$

c) The angular speed after 40 s is 139.7 rad/s

d) The wheel makes 1501 revolutions

Explanation:

The initial angular speed of the wheel is

$\omega_i = 2000 rpm$

which means 2000 revolutions per minute.

We have to convert it into rad/s. Keeping in mind that:

$1 rev = 2\pi rad$

$1 min = 60 s$

We find:

$\omega_i = 2000 \frac{rev}{min} \cdot \frac{2\pi rad/rev}{60 s/min}=209.3 rad/s$

To find the angular acceleration, we have to convert the final angular speed also from rev/min to rad/s.

Using the same procedure used in part a),

$\omega_f = 1000 \frac{rev}{min} \cdot \frac{2\pi rad/rev}{60 s/min}=104.7 rad/s$

Now we can find the angular acceleration, given by

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

where

$\omega_i = 209.3 rad/s$ is the initial angular speed

$\omega_f = 104.7 rad/s$ is the final angular speed

t = 60 s is the time interval

Substituting,

$\alpha = \frac{104.7-209.3}{60}=-1.74 rad/s^2$

To find the angular speed 40 seconds after the initial moment, we use the equivalent of the suvat equations for circular motion:

$\omega' = \omega_i + \alpha t$

where we have

$\omega_i = 209.3 rad/s$

$\alpha = -1.74 rad/s^2$

And substituting t = 40 s, we find

$\omega' = 209.3 + (-1.74)(40)=139.7 rad/s$

The angular displacement of the wheel in a certain time interval t is given by

$\theta=\omega_i t + \frac{1}{2}\alpha t^2$

where

$\omega_i = 209.3 rad/s$

$\alpha = -1.74 rad/s^2$

And substituting t = 60 s, we find:

$\theta=(209.3)(60) + \frac{1}{2}(-1.74)(60)^2=9426 rad$

So, the wheel turns 9426 radians in the 60 seconds of slowing down. Converting this value into revolutions,

$\theta = \frac{9426 rad}{2\pi rad/rev}=1501 rev$

Learn more about circular motion:

brainly.com/question/2562955

brainly.com/question/6372960

#LearnwithBrainly

8 0

3 years ago

What are four metals other than iron that can be made to exhibit magnetic properties? Fill in the blank. Every magnet has ______

Morgarella [4.7K]

Answer:

Four metals other than iron that can be made to exhibit magnetic properties are nickel, cobalt, manganese, and chromium.

two

neutral region

north

magnetic

Explanation:

PennFoster

4 0

4 years ago

A box with weight of magnitude F_G = 2.00 N is lowered by a rope down a smooth plane that is inclined at an angle φ = 30.0 degre

nexus9112 [7]

Answer:

1.8 J

Explanation:

I had this exact question today and found someone who had solved it before, this was their response to the work done by gravity. They used the name "physicsmom"

Vertical distance = 1.8 sin 30 = .9 m

W = 2 N * .9 m = 1.8J

Good luck! I hope this helps!

5 0

3 years ago

Porque fueron tan importantes las aportaciones de Galileo Galilei en la construcción y validación del conocimiento científico

iren [92.7K]

Yooo what? Sorry I’m confused

4 0

3 years ago

In a cyclic process, a gas performs 123 J of work on its surroundings per cycle. What amount of heat, if any, transfers into or

Aleks04 [339]

Answer:

123 J transfer into the gas

Explanation:

Here we know that 123 J work is done by the gas on its surrounding

So here gas is doing work against external forces

Now for cyclic process we know that

$\Delta U = 0$

so from 1st law of thermodynamics we have

$dQ = W + \Delta U$

$dQ = W$

so work done is same as the heat supplied to the system

So correct answer is

123 J transfer into the gas

4 0

3 years ago