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1 year ago

What time is the eclipse happening tonight?.

1 answer:

3 0

The first location to see the partial solar eclipse begin is at 3.58 a.m. EST (08:58 UTC), the greatest point of total solar eclipse occurs at 6 a.m. EST (11:00 UTC) and the last location to see the partial eclipse end is at 8:02 a.m. EST (13:02 UTC) according to Time and Date.

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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

2 years ago

Question 10 of 10Which statements are true?Check all that apply.O A. If heat is added to a substance, the temperature alwaysincr

inna [77]

The true statements are B and C.

This comes from the following facts:

Even when heat is added to a substance in a change of phase the temperature does not increases since this heat is latent heat.

3 0

1 year ago

A turntable reaches an angular speed of "45 rev/min" in "4.10 s" after being turned on. What is its angular acceleration?

Marina86 [1]

Answer:

1.15 rad/s²

Explanation:

given,

angular speed of turntable = 45 rpm

= $45\times \dfrac{2\pi}{60}$

= $4.71\ rad/s$

time, t = 4.10 s

initial angular speed = 0 rad/s

angular acceleration.

$\alpha = \dfrac{\omega_f-\omega_0}{t}$

$\alpha = \dfrac{4.71-0}{4.10}$

$\alpha = 1.15\ rad/s^2$

Hence, the angular acceleration of the turntable is 1.15 rad/s²

3 0

3 years ago

A 1,500 kg car hits a boulder with a force of 500 N, and the collision takes 0.5

Anuta_ua [19.1K]

Answer: C.

250 kg-m/s

Explanation:

Given that the

Mass M = 1,500 kg

Force F = 500 N

Time t = 0.5 seconds

From Newton's second law of motion which state that the rate of change of momentum is proportional to the applied force.

F = mV/t

Ft = mV

Where ft = impulse: the product of time and applied force

Substitutes force and time into the formula

Ft = 500 × 0.5 = 250 Ns

7 0

3 years ago

A hydrogen atom consists of a proton and an electron. If the orbital radius of the electron increases

tamaranim1 [39]

Answer:

The potential energy increases if the orbital radius increases.

Explanation:

The orbital radius of the electron increases means the distance from the nucleus of the hydrogen atom increase.

The nucleus is positively charged .

The potential energy is given by P.E = - $\frac{Ze^{2} }{r}$

where Z is the atomic number

r is the radius

The negative sign indicates that the electron which is revolving is bound to nucleus.

As the radius and potential energy are inversely proportional it is clear that when <em>radius increase</em> the<em> potential energy become less negative </em>which means the potential energy increases when the orbital radius increase.

5 0

3 years ago