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3 years ago

When you set something down on the ground what kind of work is your arm doing

Physics

2 answers:

Ksju [112]3 years ago

7 0

When you set something down, gravity does positive work, while YOU do negative work.

Zigmanuir [339]3 years ago

5 0

I think it would be negative apex :)

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In 2005 astronomers announced the discovery of a large black hole in the galaxy Markarian 766 having clumps of matter orbiting a

IRISSAK [1]

A. $4.64\cdot 10^{11}m$

The orbital speed of the clumps of matter around the black hole is equal to the ratio between the circumference of the orbit and the period of revolution:

$v=\frac{2\pi r}{T}$

where we have:

$v=30,000 km/s = 3\cdot 10^7 m/s$ is the orbital speed

r is the orbital radius

$T=27 h \cdot 3600 =97,200 s$ is the orbital period

Solving for r, we find the distance of the clumps of matter from the centre of the black hole:

$r=\frac{vT}{2\pi}=\frac{(3\cdot 10^7 m/s)(97200 s)}{2\pi}=4.64\cdot 10^{11}m$

B. $6.26\cdot 10^{36}kg, 3.13\cdot 10^6 M_s$

The gravitational force between the black hole and the clumps of matter provides the centripetal force that keeps the matter in circular motion:

$m\frac{v^2}{r}=\frac{GMm}{r^2}$

where

m is the mass of the clumps of matter

G is the gravitational constant

M is the mass of the black hole

Solving the formula for M, we find the mass of the black hole:

$M=\frac{v^2 r}{G}=\frac{(3\cdot 10^7 m/s)^2(4.64\cdot 10^{11} m)}{6.67\cdot 10^{-11}}=6.26\cdot 10^{36}kg$

and considering the value of the solar mass

$M_s = 2\cdot 10^{30}kg$

the mass of the black hole as a multiple of our sun's mass is

$M=\frac{6.26\cdot 10^{36} kg}{2\cdot 10^{30} kg}=3.13\cdot 10^6 M_s$

C. $9.28\cdot 10^9 m$

The radius of the event horizon is equal to the Schwarzschild radius of the black hole, which is given by

$R=\frac{2MG}{c^2}$

where M is the mass of the black hole and c is the speed of light.

Substituting numbers into the formula, we find

$R=\frac{6.26\cdot 10^{36} kg)(6.67\cdot 10^{-11})}{(3\cdot 10^8 m/s)^2}=9.28\cdot 10^9 m$

8 0

3 years ago

you ride a bike for 2 hours at 25 km/hr then 3 hours at 34 km/hr. what is your average velocity (in km/hr)?

mamaluj [8]

<h3>Answer:</h3>

30.4 km/hr

<h3>Explanation:</h3>

<u>We are given</u>;

Speed in the first 2 hours as 25 km/hr
Speed in the next 3 hours as 34 km/hr

We are required to determine the average velocity in km/hr

To get the average velocity we divide total distance by total time.
Thus, we need to determine the total distance

Distance = Speed × time

Distance covered in the first 2 hours;

= 25 km/hr × 2 hours

= 50 km

Distance in the next 3 hours

= 34 km/hr × 3 hours

= 102 km

Therefore, total distance = 50 km + 102 km

= 152 km

Total time = 2 hrs + 3 hrs

= 5 hours

Therefore;

Average speed = 152 km ÷ 5 hours

= 30.4 km/hr

Thus, the average speed is 30.4 km/hr

4 0

3 years ago

As the world population continues to rise, the demand for energy also continues to rise. Which type of fuel does little to pollu

Vlad1618 [11]

Answer:

im pretty sure nuclear if not nitrogen

Explanation:

4 0

3 years ago

Choose the correct option.

AlexFokin [52]

Answer:

These molecules push the layer of molecules down / near, so they also start to vibrate. In this way, the oscillation is followed by one molecule next to it.

3 0

2 years ago

in an experiment performed in a space station a force of 6 n causes an object to have an acceleration equal to 4 m / S2 II what

spayn [35]

F = m A

m = F / A

m = 6N / 4m/s^2

m = 1.5 kg

8 0

3 years ago