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zysi [14]
3 years ago
15

What action within the heart creates the characteristic “lib-dub” heartbeat?

Physics
2 answers:
harkovskaia [24]3 years ago
8 0
Valves of the heart oppening and closing
balu736 [363]3 years ago
8 0
A heartbeat is the sound caused by the heart valves opening and closing while they pump blood. A properly working heart only has blood flowing in one direction. This is possible by the valves opening and closing in exact coordination with the heart’s pumping action. Assuming you meant lub-dub, the lub sound is the tricuspid and mitral valves closing. The dub sound is the aortic and pulmonary valves closing. Combined, they make the sound of a heartbeat/the sound of someone's heart working properly.
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Two massless bags contain identical bricks, each brick having a mass M. Initially, each bag contains four bricks, and the bags m
stepladder [879]

Answer: F_{2}=\frac{3}{4}F_{1}

Explanation:

According to Newton's law of universal gravitation:

F=G\frac{m_{1}m_{2}}{r^2}

Where:

F is the module of the force exerted between both bodies

G is the universal gravitation constant.

m_{1} and m_{2} are the masses of both bodies.

r is the distance between both bodies

In this case we have two situations:

1) Two bags with masses 4M and 4M mutually exerting a gravitational attraction F_{1} on each other:

F_{1}=G\frac{(4M)(4M)}{r^2}   (1)

F_{1}=G\frac{16M^2}{r^2}   (2)

F_{1}=16\frac{GM^2}{r^2}   (3)

2) Two bags with masses 2M and 6M mutually exerting a gravitational attraction F_{2} on each other (assuming the distance between both bags is the same as situation 1):

F_{2}=G\frac{(2M)(6M)}{r^2}   (4)

F_{2}=G\frac{12M^2}{r^2}   (5)

F_{2}=12\frac{GM^2}{r^2}   (6)

Now, if we isolate \frac{GM^2}{r^2} from (3):

\frac{F_{1}}{16}=\frac{GM^2}{r^2}   (7)

Substituting \frac{GM^2}{r^2}  found in (7) in (6):

F_{2}=12(\frac{F_{1}}{16})   (8)

F_{2}=\frac{12}{16}F_{1}   (9)

Simplifying, we finally get the expression for F_{2}  in terms of F_{1} :

F_{2}=\frac{3}{4}F_{1}  

5 0
3 years ago
If two children, with masses of 16 kg and 24 kg , sit in seats opposite one another, what is the moment of inertia about the rot
Elena-2011 [213]

Answer:

The moment of inertia about the rotation axis is 117.45 kg-m²

Explanation:

Given that,

Mass of one child = 16 kg

Mass of second child = 24 kg

Suppose a playground toy has two seats, each 6.1 kg, attached to very light rods of length r = 1.5 m.

We need to calculate the moment of inertia

Using formula of moment of inertia

I=I_{1}+I_{2}

I=(m+m_{1})\times r^2+(m+m_{2})\times r^2

m = mass of seat

m₁ =mass of one child

m₂ = mass of second child

r = radius of rod

Put the value into the formula

I=(16+6.1)\times(1.5)^2+(24+6.1)\times(1.5)^2

I=117.45\ kg-m^2

Hence, The moment of inertia about the rotation axis is 117.45 kg-m²

8 0
3 years ago
2 (a) A plane from airport A flies 280 km to the east to airport B. The plane then travelled north to airport C, 190 km away. (i
Mekhanik [1.2K]

Answer:

See below

Explanation:

See attached diagram

280 km   east then 190 km north

Use Pythagorean theorem to find the resultant displacement

d^2 = 280^2 + 190^2

d = 338.4 km

Angle will be    arctan ( 190/280) = 34.16 °

4 0
2 years ago
What does a calorimeter measure?
DiKsa [7]
A calorimeter measures the amount of heat in a chemical reaction. So the answer would be C, specific heat.
8 0
3 years ago
A wind turbine is an example of what kind of device
Liula [17]

Answer:

it’s an example of a generator.

Explanation:

3 0
2 years ago
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