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3 years ago

An atom with 9 protons, 11 electrons, and 10 neutrons has a net charge of

1 answer:

5 0

You find net charge by subtracting the number of electrons from the number of protons (since protons are positive and electrons are negative). 9 - 10 = -1

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You’ve just discovered that you are blood type O negative, highly valuable because it can be given to almost anyone in a life-th

Karolina [17]

Answer:

A) true

33) Osha data : true

34 ) False

Explanation:

A) Karl Landsteiner was the first to classify blood on the basis of modern theory .

33) OSHA ( Occupational Safety and Health Administration ) data relates to the safety measures that are taken by a unit or firm to avoid hazardous situation for their workforce.

34 ) There are as many as 150 points in an average finger prints that can be compared. Some country like England requires 16 point identification , some like France requires 17 points identification. So The statement is wrong.

6 0

3 years ago

A reciprocating compressor is a device that compresses air by a back-and-forth straight-line motion, like a piston in a cylinder

Stella [2.4K]

Answer:

The temperature change per compression stroke is 32.48°.

Explanation:

Given that,

Angular frequency = 150 rpm

Stroke = 2.00 mol

Initial temperature = 390 K

Supplied power = -7.9 kW

Rate of heat = -1.1 kW

We need to calculate the time for compressor

Using formula of compression

$\terxt{time for compression}=\text{time for half revolution}$

$\terxt{time for compression}=\dfrac{1}{2}\times T$

$\terxt{time for compression}=\dfrac{1}{2}\times \dfrac{1}{f}$

Put the value into the formula

$\terxt{time for compression}=\dfrac{1}{2}\times \dfrac{1}{150}\times60$

$\terxt{time for compression}=0.2\ sec$

We need to calculate the rate of internal energy

Using first law of thermodynamics

$U=Q-W$

$\dfrac{\Delta U}{\Delta t}=\dfrac{\Delta Q}{\Delta t}-\dfrac{\Delta W}{\Delta t}$

Put the value into the formula

$\dfrac{\Delta U}{\Delta t}=(-1.1)-(7.9)$

$\dfrac{\Delta U}{\Delta t}=6.8\ kW$

We need to calculate the temperature change per compression stroke

Using formula of rate of internal energy

$\dfrac{\Delta U}{\Delta t}=\dfrac{nc_{v}\Delta \theta}{\Delta t}$

$\Delta\theta=\dfrac{\Delta U}{\Delta t}\times\dfrac{\Delta t}{n\times c_{c}}$

Put the value into the formula

$\Delta \theta=6.8\times10^{3}\dfrac{0.2}{2.0\times20.93}$

$\Delta\theta=32.48^{\circ}$

Hence, The temperature change per compression stroke is 32.48°.

6 0

3 years ago

When a plane flies with the wind, it can travel 1575 miles in 3.5 hours. when the plane flies in the opposite direction, again

Zepler [3.9K]

When plane is flying along the wind then we can say

$V_{plane} + v_{wind} = \frac{distance}{time}$

$V_{plane} + v_{wind} = \frac{1575}{3.5}$

$V_{plane} + v_{wind} = 450 mph$

Now when its going against the wind the speed is given by

$V_{plane} - v_{wind} = \frac{distance}{time}$

$V_{plane} - v_{wind} = \frac{1575}{4.5}$

$V_{plane} - v_{wind} = 350 mph$

Now by the above two equations we will have

$V_{plane} = 400 mph$

$v_{wind} = 50 mph$

3 0

3 years ago

The mass of a certain neutron star is 2.5x10^30kg and the radius 7000m. what is the force of gravity on a 1kg object of the surf

Makovka662 [10]

Answer:

3.42N

Explanation:

*not too sure bc i left my physics notes at school so it might not be 100% accurate :p*

Use the equation: F = (GMm)/(r^2)

F = force of gravity

G = gravitational constant (6.7x10^-11)

M = mass1 (2.5x10^30kg)

m = mass2 (1kg)

r = radius (7000m)

Plug it in: F = ((6.7x10^-11)(2.5x10^30)(1)) / (7000^2)

F = (1.675x10^20) / (4.9x10^7)

F = 3.4183673x10^12

F = 3.42N

8 0

3 years ago

A(n) _____ is a gap in the geologic record where some rock layers have been lost because of erosion.

Elenna [48]

I'm not sure, I think it's option A.

Let me know if I'm wrong!

4 0

4 years ago