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3 years ago

Anyone know how to select someone as brainiest?!!!!!!!!!!!!!!!

Physics

2 answers:

Zepler [3.9K]3 years ago

7 0

Where’s the work????????

Bingel [31]3 years ago

3 0

You press the button near their answer

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What type of star has an absolute brightness of −3 and a surface temperature around 20,000 °C?

lara31 [8.8K]

Answer:

Explanation:

5 0

4 years ago

Read 2 more answers

There is a maximum depth at which a diver can breathe through a snorkel tube because as the depth increases, so does the pressur

hammer [34]

Answer: $59.78\times 10^3\ Pa$

Explanation:

Given

Diver is at a depth of $h=6.1\ m$ inside the water $(\rho=10^3\ kg/m^3)$

As we go down pressure increases due to the weight of liquid column above us

Pressure difference is given by $P=\rho \times g \times h$

Where $\rho$ =density of liquid

h=depth

g=acceleration due to gravity

So external-internal pressure difference is

$\Delta P=10^3\times 9.8\times 6.1$

$\Delta P=59.78\times 10^3\ Pa$

8 0

3 years ago

Truck A has a mass of 5000 kg and a velocity of +5m/s. Explain why we say truck B has a velocity of -5m/s.

frez [133]

Velocity is a vector, which includes both magnitude and direction. Negative velocity means that B is travelling in an opposite direction of A.

4 0

3 years ago

The specific heat of aluminum is 0.90 J/gC . How much heat is given off when 25 grams of aluminum is cooled from 55 C to 25 C?

xxMikexx [17]

Answer:

Q = 675 [J]

Explanation:

We can calculate the amount of heat transfer by means of the following expression that includes the mass and temperature change in a body as a function of the specific heat.

$Q=m*C_{p}*(T_{initial}-T_{final})$

where:

m = mass = 25 [gr]

Cp = specific heat = 0.9 [J/g*°C]

Tinitial = 55 [°C]

Tfinal = 25 [°C]

$Q=25*0.9*(55-25)\\Q=675 [J]$

4 0

3 years ago

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