A car travels 500m in 50s, then 1,500m in 75s. Calculate its averages speed for the whole journey

A propagating wave in space with electric and magnetic components. These components oscillate at right angles to each other. It

Yuliya22 [3333]

Response:

electromagnetic

Clarification:

8 0

3 months ago

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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

Sav [3153]

Complete Question

Standing up quickly from a lying position may lead to dizziness or faintness. This occurs because the blood vessels cannot dilate sufficiently to adjust for the sudden drop in blood pressure. If your brain is 0.4 m above your heart when you are upright, what is the difference in blood pressure between these two points? The density of blood plasma is approximately 1025 kg/m3, and the typical systolic blood pressure at the heart is 120 mm of Hg (which is equal to 0.16 atm, 16 kP, or 1.6 × 104 N/m2).

Answer:

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

Explanation:

It is generally represented mathematically as

$P = \rho gh$

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

We can express the pressure difference between the brain and the heart as

$P = 1025 * 9.8 *0.4$

$= 4018 N/m^2$

The blood pressure at the heart is given as

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

Now, the calculated pressure at the brain becomes

$P_b = P_h - P$

$= 1.596*10^4 - 4018$

$= 11982 N/m^2$

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

3 0

3 months ago

Consider a bicycle wheel to be a ring of radius 30 cm and mass 1.5 kg. Neglect the mass of the axle and sprocket. If a force of

kicyunya [3294]

Answer:

The angular speed after 6 seconds is $\omega = 1466.67s^{-1}$ .

Explanation:

The formula

$I\alpha = Fd$

connects the moment of inertia $I$ of a rigid body, the angular acceleration $\alpha$ , and the force applied $F$ at a distance $d$ from the rotation axis.

In this scenario, the force applied equals $F = 22N$ , at a distance $d = 6cm =0.06m$ , to a ring with a moment of inertia of $I =mr^2$ ; hence, the angular acceleration is

$\alpha =\frac{Fd}{I}$

$\alpha =\frac{22N*0.06m}{(1.5kg)*(0.06)^2}$

$\alpha = 244.44\: s^{-2}$

Thus, the angular speed $\omega$ which after 6 seconds is

$\omega = \alpha t$

7 0

2 months ago