A maglev train can “float” because magnets in the bottom of the train and on the guideway...

Earth's rotational axis completes one precession every _____.

ruslelena [56]

A). Earth completes one rotation on its rotation axis
every (3 minutes and 56 seconds less than 24 hours).
This causes night and day. It's rotation, not precession.

B). Earth completes one orbital revolution around the sun
every (365 plus a little bit) days. It's revolution, not precession.

C). I'm not sure what happens on a cycle of 512 years.
It may have something to do with the moon. But whatever
it is, it's not precession.

D). When you spin a top and it starts to run down, the first
thing that happens is that the handle of the top, or the point
on top of the top, starts moving in a circle. That's precession.
That's what the Earth's axis is doing. The north pole points
toward the north star (Polaris) now. But the north pole is
actually drawing out a big circle in the sky, and other stars
will become the "north star" far in the future.
The north pole draws out a full circle in the sky, roughly
once every 26,000 years. That's precession.

6 0

4 years ago

A force F acts in the forward direction on a cart of mass m. A friction force ff opposes this motion. Part A Use Newton's second

stellarik [79]

Answer:

a = F-ff/m

Explanation:

According to Newton's second law of motion which states that "the rate of change in momentum of a body is directly proportional to the applied force F and acts in the direction of the force.

Mathematically;

F = ma

Since two forces acts on the cart i.e the moving force F and the frictional force Ff , we will take the sum of the forces.

∑F = ma where

m is the mass of the cart

a is its acceleration

∑F = F+(-ff )(since frictional force is an opposing force)

F - ff = ma

Dividing both sides by mass m

a = F-ff/m

5 0

3 years ago

Six artificial satellites circle a space station at constant speed. The mass m of each satellite, distance L from the space stat

nikklg [1K]

Answers:

a) $T_{2}>T_{5}>T_{1}>T_{3}=T_{6}>T_{4}$

b) $a_{4}>a_{6}>a_{1}>a_{3}>a_{5}>a_{2}$

Explanation:

a) Since we are told the satellites circle the space station at constant speed, we can assume they follow a uniform circular motion and their tangential speeds $V$ are given by:

$V=\omega L=\frac{2\pi}{T} L$ (1)

Where:

$\omega$ is the angular frequency

$L$ is the radius of the orbit of each satellite

$T$ is the period of the orbit of each satellite

Isolating $T$ :

$T=\frac{2 \pi L}{V}$ (2)

Applying this equation to each satellite:

$T_{1}=\frac{2 \pi L}{V_{1}}=261.79 s$ (3)

$T_{2}=\frac{2 \pi L}{V_{2}}=1570.79 s$ (4)

$T_{3}=\frac{2 \pi L}{V_{3}}=196.349 s$ (5)

$T_{4}=\frac{2 \pi L}{V_{4}}=98.174 s$ (6)

$T_{5}=\frac{2 \pi L}{V_{5}}=785.398 s$ (7)

$T_{6}=\frac{2 \pi L}{V_{6}}=196.349 s$ (8)

Ordering this periods from largest to smallest:

$T_{2}>T_{5}>T_{1}>T_{3}=T_{6}>T_{4}$

b) Acceleration $a$ is defined as the variation of velocity in time:

$a=\frac{V}{T}$ (9)

Applying this equation to each satellite:

$a_{1}=\frac{V_{1}}{T_{1}}=0.458 m/s^{2}$ (10)

$a_{2}=\frac{V_{2}}{T_{2}}=0.0254 m/s^{2}$ (11)

$a_{3}=\frac{V_{3}}{T_{3}}=0.4074 m/s^{2}$ (12)

$a_{4}=\frac{V_{4}}{T_{4}}=1.629 m/s^{2}$ (13)

$a_{5}=\frac{V_{5}}{T_{5}}=0.101 m/s^{2}$ (14)

$a_{6}=\frac{V_{6}}{T_{6}}=0.814 m/s^{2}$ (15)

Ordering this acceerations from largest to smallest:

$a_{4}>a_{6}>a_{1}>a_{3}>a_{5}>a_{2}$

4 0

3 years ago

In which situation is work not being done?

almond37 [142]

AS

work done =W = F.d = F d cosФ (Ф is angle between force F and displacement d) If a body/object is moving on a smooth surface (friction-less surface ) .There is no force acting on that body. F=0 so W=FdcosФ= (0)dcosФ ⇒ W=0

Now if a body is facing some amount of force but under the action of force there is no displacement covered. d=0 so W =FdcosФ= F(0)cosФ ⇒W=0

example: A person is applying a force on rigid wall but wall remains at rest there is no displacement occurs in wall.

The third term upon which work done dependent is angle between force and displacement i.e Ф. If Ф=90° then W= FdcosФ= Fdcos90⇒ W=0 ( as cos 90°=0)

5 0

3 years ago

What kind of light results when the total spectrum of refracted light is recombined? violet green white red?

ElenaW [278]

Hello
The final light will be white. In fact, each color of the visible spectrum is an electromagnetic wave with its own specific frequency and wavelength. White, instead, does not have a specific frequency: it is the sum of all the different wavelengths of the visible spectrum. Therefore, when recombining the spectrum of the refracted light all the different frequencies recombine together, and their sum gives white light.

(edited)

4 0

3 years ago