What is the prefix for ecosystem and what does the prefix mean

If you are lying down and stand up quickly, you can get dizzy or feel faint. This is because the blood vessels don't have time t

sammy [17]

Complete Question

If you are lying down and stand up quickly, you can get dizzy or feel faint. This is because the blood vessels don’t have time to expand to compensate for the blood pressure drop. If your brain is 0.4 m higher than your heart when you are standing, how much lower is your blood pressure at your brain than it is at your heart? The density of blood plasma is about 1025 kg/m3 and a typical maximum (systolic) pressure of the blood at the heart is 120 mm of Hg (= 0.16 atm = 16 kP = 1.6 × 104 N/m2).

Answer:

The pressure at the brain is $P_b = 89.872 \ mm \ of \ Hg$

Explanation:

Generally is mathematically denoted as

$P = \rho gh$

Substituting $1025 kg/m^3$ for $\rho$ (the density) , $9.8 m/s^2$ for g (acceleration due to gravity) , 0.4m for h (the height )

We have that the pressure difference between the heart and the brain is

$P = 1025 * 9.8 *0.4$

$= 4018 N/m^2$

But the pressure of blood at the heart is given as

$P_h=120 mm of Hg =$ $120 * 133 = 1.59*10^3Pa$

Now the pressure at the brain is mathematically evaluated as

$P_b = P_h - P$

$= 1.596*10^4 - 4018$

$= 11982 N/m^2$

$P_b= \frac{11982}{133} = 89.872 \ mm \ of \ Hg$

3 0

4 years ago

A bungee jumper jumps off a bridge and bounces up and down several times.

Stella [2.4K]

The energy that was lost due to air resistance while she was bouncing is determined as 3,360 J.

<h3>Conservation of energy</h3>

The amount of energy lost due to air resistance while she was bouncing is determined from the principle of conservation of energy.

ΔE = P.E - Ux

ΔE = mgh - ¹/₂kx²

ΔE = (50)(9.8)(16) - ¹/₂(35)(16)²

ΔE = 3,360 J

Thus, the energy that was lost due to air resistance while she was bouncing is determined as 3,360 J.

Learn more about energy here: brainly.com/question/13881533

#SPJ1

3 0

2 years ago

You place a 10 kg block on a ramp with an angle of 20 degrees. You push the block up the ramp giving it an initial velocity of 1

Ainat [17]

Answer:

L = 15.97 m

Explanation:

Given:-

- The mass of the block, m = 10 kg

- The inclination of ramp, θ = 20°

- The initial speed, Vi = 15 m/s

- The coefficient of friction u = 0.4

Find:-

find the total distance the block travels before it turns around and slides back down the ramp.

Solution:-

- The total distance travelled by the block up the ramp is defined when all the kinetic energy is converted into potential energy and work is done against the friction. Final velocity V2 = 0.

- Develop a free body diagram of the block. Resolve the weight "W" of the block normal to the surface of ramp. Then apply equilibrium condition for the block in the direction normal to the surface:

N - W*cos( θ ) = 0

Where, N : The contact force between block and ramp.

N = m*g*cos ( θ )

- The friction force (Ff) is defined as:

Ff = u*N

Ff = u*m*g*cos ( θ )

- Apply the work-energy principle for the block which travels a distance of "L" up the ramp:

K.E i = P.E f + Work done against friction

Where, K.E i = 0.5*m*Vi^2

P.E f = m*g*L*sin( θ )

Work done = Ff*L

- Evaluate "L":

0.5*m*Vi^2 = m*g*L*sin( θ ) + u*m*g*cos ( θ )*L

0.5*Vi^2 = g*L*sin( θ ) + u*g*cos ( θ )*L

0.5*Vi^2 = L [ g*sin( θ ) + u*g*cos ( θ ) ]

L = 0.5*Vi^2 / [ g*sin( θ ) + u*g*cos ( θ ) ]

L = 0.5*15^2 / [ 9.81*sin( 20 ) + 0.4*9.81*cos ( 20 ) ]

L = 15.97 m

7 0

4 years ago

If a rock is dropped with a weight of 50kg and friction due to air resistance produces a force of 98N, what is the net force in

bearhunter [10]

Answer:

The net force is 392N, pointing down.

Explanation:

The net force is the sum of all forces acting on the rock, namely the gravity ("+" acting downward) and the friction force due to air resistance ("-" acting upward):

$F_{net} = F_g - F_{air}\\F_{net} = m\cdot g - F_{air} = 50kg\cdot 9.8\frac{m}{s^2}-98N= (490-98)N=392N$

The net force is 392N and pointing down (positive)/

8 0

4 years ago

A bike traveling initially at a speed of 32 m/s accelerates

Vika [28.1K]

<u>We are given:</u>

Initial velocity (u) = 32 m/s

Acceleration (a) = 3 m/s²

Displacement (s) = 40 m

Final Velocity (v) = v m/s

<u>Solving for the Final Velocity:</u>

from the third equation of motion:

v² - u² = 2as

<em>replacing the variables</em>

v² - (32)² = 2(3)(40)

v² = 240 + 1024

v² = 1264

v = √1264

v = 35.5 m/s

Therefore, the velocity of the bike after travelling 40 m is 35.5 m/s

4 0

3 years ago