Answer:
That scenario can be explained by the idea of the contribution of dark matter on that point.
Explanation:
It can be explained through the idea of dark matter, this one was born to explain why stars (or any object) that were farther for the supermassive black hole in the center of the Milky Way galaxy didn't decrease it rotational velocity as it was expected according to equation 1.
(1)
Where v is the rotational velocity, G is the gravitational constant, M is the mass of the supermassive black hole, and r is the orbital radius.
Notice, that If the distance increases the orbital speed decreases (inversely proportional).
The third choice is correct
Answer:
thick wire and cold temperatures
Answer:
Explanation:
Given that
The mass of the body is 0.04kg
M=0.04kg
The radius of the paths is 0.6m
r=0.6m
The normal force exerted at A is 3.9N
Fa=3.9N
The normal force exerted at B is 0.69N
Fb=0.69N
Then work done by friction from point A to B will be the change in K.E
W=∆K.E+P.E
So we need to know the velocity at both point A and B
Then since the centripetal force is given as
Ft=mv²/r
Then,
For point A
Fa=mv²/r
3.9=0.04v²/0.6
3.9=0.0667v²
v²=3.9/0.0667
v²=58.5
v=√58.5
v=7.65m/s
Va=7.65m/s
Now at point B
Fb=mv²/r
0.69=0.04v²/0.6
0.69=0.0667v²
v²=0.69/0.0667
v²=10.35
v=√10.35
v=3.22m/s
Vb=3.22m/s
Then, the work done is
W=∆K.E+P.E
P.E is given as mgh
The height will be 2R =1.2m
P.E=mgh
P.E=0.04×9.81×1.2
P.E=0.471J
Final kinetic energy at B minus initial kinetic energy at A
W=K.Eb-K.Ea
K.E is given as 1/2mv²
W=1/2m(Vb²-Va²) +P.E
W=0.5×0.04(3.22²-7.65²) +0.471
W=0.5×0.04×(-48.1541) +0.471
W=-0.96+0.471
W=-0.49J
work was done on the block by friction during the motion of the block from point A to point B is 0.49J.
Friction opposes motions and that is why the work done is negative
When you look at this, you might not be sure which way to divide ...
Should you divide 6 by 5 or 5 by 6 ?
Here's a case where you can use your units to decide.
The question wants to know the 'period'. That's a length of time,
so the answer needs to have units of time.
If you divide 'cycles' be 'time', you'll get 'cycles/second'.
That's Hz. It's frequency, not time.
If you divide 'time' by 'cycles', you'll get 'seconds/cycle'.
That's time, and it's exactly the definition of 'period'.
Period = (6 seconds) / (5 cycles)
= (6 / 5) seconds/cycle
= 1.2 seconds
