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mr Goodwill [35]
3 years ago
12

There are seven major levels of classification. Kingdom and phylum are just two of the levels. Which of the following are also m

ajor levels of classification Choose all answers that are correct. A. Class B. Order C. Family Or D. Level
Physics
1 answer:
umka2103 [35]3 years ago
5 0
The answer is B and C which is order and family! My sister had this question!
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6) Find the speed a spherical raindrop would attain by falling from 4.00 km. Do this:a) In the absence of air dragb) In the pres
sleet_krkn [62]

We are asked to determine the velocity of a rain drop if it falls from 4 km.

To do that we will use the following formula:

2ah=v_f^2-v_0^2

Where:

\begin{gathered} a=\text{ acceleration} \\ h=\text{ height} \\ v_f,v_0=\text{ final and initial velocity} \end{gathered}

If we assume the initial velocity to be 0 we get:

2ah=v_f^2

The acceleration is the acceleration due to gravity:

2gh=v_f^2

Now, we take the square root to both sides:

\sqrt{2gh}=v_f

Now, we substitute the values:

\sqrt{2(9.8\frac{m}{s^2})(4000m)}=v_f

solving the operations:

280\frac{m}{s}=v

Therefore, the velocity without air drag is 280 m/s.

Part B. we are asked to determine the velocity if there is air drag. To do that we will use the following formula:

F_d=\frac{1}{2}C\rho_{air}Av^2

Where:

\begin{gathered} F_d=drag\text{ force} \\ C=\text{ constant} \\ \rho_{air}=\text{ density of air} \\ A=\text{ area} \\ v=\text{ velocity} \end{gathered}

We need to determine the drag force. To do that we will use the following free-body diagram:

Since the velocity that the raindrop reaches is the terminal velocity and its a constant velocity this means that the acceleration is zero and therefore the forces are balanced:

F_d=mg

Now, we determine the mass of the raindrop using the following formula:

m=\rho_{water}V

Where:

\begin{gathered} \rho_{water}=\text{ density of water} \\ V=\text{ volume} \end{gathered}

The volume is the volume of a sphere, therefore:

m=\rho_{water}(\frac{4}{3}\pi r^3)

Since the diameter of the raindrop is 3 millimeters, the radius is 1.5 mm or 0.0015 meters. Substituting we get:

m=(0.98\times10^3\frac{kg}{m^3})(\frac{4}{3}\pi(0.0015m)^3)

Solving the operations:

m=1.39\times10^{-5}kg

Now, we substitute the values in the formula for the drag force:

F_d=(1.39\times10^{-5}kg)(9.8\frac{m}{s^2})

Solving the operations:

F_d=1.36\times10^{-4}N

Now, we substitute in the formula:

1.36\times10^{-4}N=\frac{1}{2}C\rho_{air}Av^2

Now, we solve for the velocity:

\frac{1.36\times10^{-4}N}{\frac{1}{2}C\rho_{air}A}=v^2

Now, we substitute the values. We will use the area of a circle:

\frac{1.36\times10^{-4}N}{\frac{1}{2}(0.45)(1.21\frac{kg}{m^3})(\pi r^2)}=v^2

Substituting the radius:

\frac{1.36\cdot10^{-4}N}{\frac{1}{2}(0.45)(1.21\frac{kg}{m^{3}})(\pi(0.0015m)^2)}=v^2

Solving the operations:

70.67\frac{m^2}{s^2}=v^2

Now, we take the square root to both sides:

\begin{gathered} \sqrt{70.67\frac{m^2}{s^2}}=v \\  \\ 8.4\frac{m}{s}=v \\  \end{gathered}

Therefore, the velocity is 8.4 m/s

7 0
10 months ago
Calculate the density of a material that has a bat a mass of 52.457 g any volume of 13.5 cm³
3241004551 [841]
Answer:
d = 3.8857 g/cm^3

Explain:
Formula/: d = m/V

Hope this helps!
(a brainliest would be appreciated)
4 0
3 years ago
An electric train moving at 5m/s accelerates to a speed of 8m/s in 20 seconds. Fine the distance travelled in meters during the
adelina 88 [10]
<h3>Answer:  130 meters</h3>

===================================================

Explanation:

vi = 5 and vf = 8 are the initial and final velocities respectively. The change in time is t = 20 seconds.

So,

x = 0.5*(vi + vf)*t

x = 0.5*(5+8)*20

x = 130 meters

represents the distance traveled. The first equation shown above is one of the four kinematics equations.

3 0
3 years ago
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Lubov Fominskaja [6]
A false positive<span> is a conclusion that some effect occurred when in fact it did not. hope it helped but i am not 100%

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7 0
3 years ago
6) The best way to reduce force in a car wreck when impulse stays the same is to
UkoKoshka [18]

Answer:

c. increase momentum

Explanation:

When cars bounce off each other, or rebound, there is a larger change in momentum and therefore a larger impulse. A larger impulse means that a greater force is experienced by the occupants of the cars. When cars crumple together, there is a smaller change in momentum and therefore a smaller impulse.

3 0
2 years ago
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