5. This break-dancer's speed is not changing as he spins on his head, but he is

Whenever two apollo astronauts were on the surface of the moon, a third astronaut orbited the moon. assume the orbit to be circu

almond37 [142]

Missing question:
"Determine (a) the astronaut’s orbital speed v and (b) the period of the orbit"

Solution

part a) The center of the orbit of the third astronaut is located at the center of the moon. This means that the radius of the orbit is the sum of the Moon's radius r0 and the altitude ( $h=430 km=4.3 \cdot 10^5 m$ ) of the orbit:
$r= r_0 + h=1.7 \cdot 10^6 m + 4.3 \cdot 10^5 m=2.13 \cdot 10^6 m$
This is a circular motion, where the centripetal acceleration is equal to the gravitational acceleration g at this altitude. The problem says that at this altitude, $g=1.08 m/s^2$ . So we can write
$g=a_c= \frac{v^2}{r}$
where $a_c$ is the centripetal acceleration and v is the speed of the astronaut. Re-arranging it we can find v:
$v= \sqrt{g r}= \sqrt{(1.08 m/s^2)(2.13 \cdot 10^6 m)}=1517 m/s = 1.52 km/s$

part b) The orbit has a circumference of $2 \pi r$ , and the astronaut is covering it at a speed equal to v. Therefore, the period of the orbit is
$T= \frac{2 \pi r}{v} = \frac{2\pi (2.13 \cdot 10^6 m)}{1517 m/s} =8818 s = 2.45 h$
So, the period of the orbit is 2.45 hours.

6 0

3 years ago

Faça uma redação sobre '' A luta das mulheres brasileiras pelos seus direitos ''

Kazeer [188]

DO YOU HAVE THE ENGLISH TRANSLATION?

5 0

3 years ago

A small cork with an excess charge of +6.0µC is placed 0.12 m from another cork, which carries a charge of -4.3µC.

Volgvan

A) 16.1 N

The magnitude of the electric force between the corks is given by Coulomb's law:

$F=k\frac{q_1 q_2}{r^2}$

where

k is the Coulomb's constant

$q_1 = 6.0 \mu C=6.0 \cdot 10^{-6} C$ is the magnitude of the charge on the first cork

$q_2 = 4.3 \mu C = 4.3 \cdot 10^{-6}C$ is the magnitude of the charge of the second cork

r = 0.12 m is the separation between the two corks

Substituting numbers into the formula, we find

$F=(9\cdot 10^9 N m^2 C^{-2} )\frac{(6.0\cdot 10^{-6}C)(4.3\cdot 10^{-6} C)}{(0.12 m)^2}=16.1 N$

B) Attractive

According to Coulomb's law, the direction of the electric force between two charged objects depends on the sign of the charge of the two objects.

In particular, we have:

- if the two objects have charges with same sign (e.g. positive-positive or negative-negative), the force is repulsive

- if the two objects have charges with opposite sign (e.g. positive-negative), the force is attractive

In this problem, we have

Cork 1 has a positive charge

Cork 2 has a negative charge

So, the force between them is attractive.

C) $2.69\cdot 10^{13}$

The net charge of the negative cork is

$q_2 = -4.3 \cdot 10^{-6}C$

We know that the charge of a single electron is

$e=-1.6\cdot 10^{-19}C$

The net charge on the negative cork is due to the presence of N excess electrons, so we can write

$q_2 = Ne$

and solving for N, we find the number of excess electrons:

$N=\frac{q_2}{e}=\frac{-4.3\cdot 10^{-6} C}{-1.6\cdot 10^{-19} C}=2.69\cdot 10^{13}$

D) $3.75\cdot 10^{13}$

The net charge on the positive cork is

$q_1 = +6.0\cdot 10^{-6}C$

We know that the charge of a single electron is

$e=-1.6\cdot 10^{-19}C$

The net charge on the positive cork is due to the "absence" of N excess electrons, so we can write

$q_1 = -Ne$

and solving for N, we find the number of electrons lost by the cork:

$N=-\frac{q_1}{e}=-\frac{+6.0\cdot 10^{-6} C}{-1.6\cdot 10^{-19} C}=3.75\cdot 10^{13}$

6 0

3 years ago

Imagine that you are jumping up and down on a trampoline.

lions [1.4K]

Answer:

a. When you are pressing downwards the energy stored is potential elastic energy due to the elasticity of the stretchy skin.

b. When you are high up in the air the energy stored is potential energy due to your weight and the distance to the ground.

Hope this Helps!

If you have Any questions Please Ask.

5 0

2 years ago

Describe what happens in a chemical reaction

ollegr [7]

Answer:

LA REPUESTA CORRECTA ES

Explanation:

7 0

3 years ago

Read 2 more answers