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3 years ago

The heart has structures that are called_____. This allows the blood to move in one direction.

Physics

2 answers:

Anarel [89]3 years ago

5 0

Answer:

valves

The heart has four valves - one for each chamber of the heart. The valves keep blood moving through the heart in the right direction.

spayn [35]3 years ago

4 0

Answer:

Valves

Explanation:

The valves help the blood move in just one direction while the veins are many.

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A diffraction grating with 140 slits per centimeter is used to measure the wavelengths emitted by hydrogen gas. At what angles i

Degger [83]

Answer:

0.003181 radians

0.003005 radians

Explanation:

Number of slits = 140 /cm

λ = Wavelength = 434 nm = 434×10⁻⁹ m

m = 3 Third order spectrum

Space between slits

$d=\frac{0.01}{140} =7.14\times 10^{-5}\ m$

Now,

$dsin\theta = m\lambda\\\Rightarrow \theta=sin^{-1}\left(\frac{m\lambda}{d}\right)\\\Rightarrow \theta=sin^{-1}\left(\frac{3\times 434\times 10^{-9}}{7.14\times 10^{-5}}\right)\\\Rightarrow \theta=sin^{-1}0.018228\\\Rightarrow \theta=0.01823^{\circ}=0.01823\times \frac{\pi}{180}=0.003181 radians$

0.003181 radians

When λ = 410 nm = 410×10⁻⁹ m

$dsin\theta = m\lambda\\\Rightarrow \theta=sin^{-1}\left(\frac{m\lambda}{d}\right)\\\Rightarrow \theta=sin^{-1}\left(\frac{3\times 410\times 10^{-9}}{7.14\times 10^{-5}}\right)\\\Rightarrow \theta=sin^{-1}0.01722\\\Rightarrow \theta=0.01722^{\circ}=0.01722\times \frac{\pi}{180}=0.003005 radians$

0.003005 radians

5 0

4 years ago

A heavy piece of hanging sculpture is suspended by a90-cm-long, 5.0 g steel wire. When the wind

Yuliya22 [10]

As we know that fundamental frequency is given as

$f = \frac{1}{2L}\sqrt{\frac{T}{\mu}}$

here we know that

$\mu = \frac{m}{l}$

here we have

m = mass of wire = 5 g

l = length of wire = 90 cm

$\mu = \frac{0.005}{0.90} kg/m$

$\mu = 5.56 \times 10^{-3} kg/m$

from above formula now

$80 = \frac{1}{2(0.90)}\sqrt{\frac{T}{5.56\times 10^{-3}}}$

$144 = \sqrt{180 T}$

$T = 115.2 N$

now we know that tension is due to weight of the sculpture so we will have

$Mg = 115.2 N$

$M = 11.76 kg$

so its mass will be 11.76 kg

6 0

4 years ago

A disk has 128 tracks of 32 sectors each, on each surface of eight platters. The disk spins at 3600 RPM and takes 15 ms to move

Serga [27]

Answer:

the longest time needed to read an arbitrary sector located anywhere on the disk is 2971.24 ms

Explanation:

Given the data in the question;

first we determine the rotational latency

Rotational latency = 60/(3600×2) = 0.008333 s = 8.33 ms

To get the longest time, lets assume the sector will be found at the last track.

hence we will access all the track, meaning that 127 transitions will be done;

so the track changing time = 127 × 15 = 1905 ms

also, we will look for the sectors, for every track rotations that will be done;

128 × 8.33 = 1066.24 ms

∴The Total Time = 1066.24 ms + 1905 ms

Total Time = 2971.24 ms

Therefore, the longest time needed to read an arbitrary sector located anywhere on the disk is 2971.24 ms

7 0

3 years ago

A 0.015 kg marble sliding to the right at 22.5 cm/s on a frictionless surface makes an elastic head-on collision with a 0.015 kg

slava [35]

Answer:

Explanation:

mass of first marble $m_1=m=0.015\ kg$

Initial velocity of the first marble $u_1=22.5\ m/s$

considering right side as positive

Mass of second marble

$m_2=m=0.015\ kg\\u_2=-18\ cm/s$

After collision first marble moves to the left with a velocity of 18 cm/s

i.e. $v_1=-18\ cm/s$

considering $v_2$ be the velocity of second marble after collision

The Coefficient of restitution is 1 for an elastic collision

$e=\frac{v_2-v_1}{u_1-u_2}$

Putting values

$1=\frac{v_2-(-18)}{22.5-(-18)}\\22.5+18=v_2+18\\v_2=22.5\ m/s$

So, the velocity of the second marble is 22.5 m/s to the right after the collision

(b)Initial kinetic energy = $0.5\times 0.015\times (22.5\times 10^{-2})^2+0.5\times 0.015\times (18\times 10^{-2})^2=6.22\times 10^{-4}\ J$

Final kinetic energy=

$0.5\times 0.015\times (18\times 10^{-2})^2+0.5\times 0.015\times (22.5\times 10^{-2})^2=6.22\times 10^{-4}\ J$

6 0

3 years ago

Which best explains why people see carrots as orange

Andru [333]

Beta Carotene is the reason why a carrot is orange. Carotene is a color pigment that is found in large quantities in carrots and it has health benefits as well. The main health benefit of carotene is that our body converts it into vitamin A which is essential.

8 0

4 years ago

Read 2 more answers