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3 years ago

Dark matter may explain _____.

Physics

2 answers:

tia_tia [17]3 years ago

5 0

Answer: A.unexpected orbital velocities of stars in galaxies

Explanation:

Dark Matter makes up about 80% of matter in the universe. This matter does not emit light and hence, it is called dark matter as it cannot be observed directly.

The effect of the presence of the dark matter is unexpected orbital velocities of stars in galaxies. At the center, the orbital velocities are greater than those at the edge. Had there been no dark matter, the galaxy would have flown apart.

Lisa [10]3 years ago

4 0

Dark matter may explain <span>unexpected orbital velocities of stars in galaxies.</span>

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Three sleds (30kg sled connected by tension rope B to 20kg sled connected by tension rope A to 10kg sled) are being pulled horiz

SOVA2 [1]

Answer:

a) a = 2.383 m / s², b) T₂ = 120,617 N , c) T₃ = 72,957 N

Explanation:

This is an exercise of Newton's second law let's fix a horizontal frame of reference

in this case the mass of the sleds is 30, 20 10 kg from the last to the first, in the first the horizontal force is applied.

a) request the acceleration of the system

we can take the sledges together and write Newton's second law

T = (m₁ + m₂ + m₃) a

a = T / (m₁ + m₂ + m₃)

a = 143 / (10 +20 +30)

a = 2.383 m / s²

b) the tension of the cables we think through cable A between the sledges of 1 and 20 kg

on the sled of m₁ = 10 kg

T - T₂ = m₁ a

in this case T₂ is the cable tension

T₂ = T - m₁ a

T₂ = 143 - 10 2,383

T₂ = 120,617 N

c) The cable tension between the masses of 20 and 30 kg

T₂ - T₃ = m₂ a

T₃ = T₂ -m₂ a

T₃ = 120,617 - 20 2,383

T₃ = 72,957 N

8 0

3 years ago

The middle one please need done in 45min

netineya [11]

Answer:

600 J

Explanation:

it's obviously btw so yeahhhh

5 0

3 years ago

Ezra is pulling a sled, filled with snow, by pulling on a rope attached to the sled. The rope makes an angle θ with respect to t

svetoff [14.1K]

Answer:

Explanation:

Given

rope makes an angle of $\theta$

Mass of sled and snow is m

Normal Force $=F_N$

applied Force is F

as Force is pulling in nature therefore normal reaction is given by

$F_N=mg-F\sin \theta$

Also $F\cos \theta =f_r$

$f_r=\mu _k\cdot F_N$

$f_r=\mu _k\cdot (mg-F\sin \theta )$

$F\cos \theta =\mu _kF_N$ -------1

$F\sin \theta =mg-F_N$ ---------2

Squaring 1 & 2 and then adding

$F^2=(\mu _kF_N)^2+(mg-F_N)^2$

$F=\sqrt{(\mu _kF_N)^2+(mg-F_N)^2}$

Substitute value of F in 1

$cos\theta =\frac{\mu _KF_N}{\sqrt{(\mu _kF_N)^2+(mg-F_N)^2}}$

$\theta =cos^{-1}(\frac{\mu _KF_N}{\sqrt{(\mu _kF_N)^2+(mg-F_N)^2}})$

8 0

3 years ago

An upward force act on a proton as it moves with a speed of 2.0 x 10^5 meters/seconds through a magnetic field of 8.5 x 10^2

Gekata [30.6K]

Force on a moving charge is given by formula

$\vec F = q(\vec v \times \vec B)$

here we know that this force will be maximum when velocity is perpendicular to magnetic field

$\vec F = qvB$

here we know that

$v = 2.0 \times 10^5 m/s$

$q = 1.6 \times 10^{-19} C$

$B = 8.5 \times 10^2 T$

now we have

$F = (1.6 \times 10^{-19})(2 \times 10^5)(8.5 \times 10^2)$

$F = 2.72 \times 10^{-11} N$

7 0

3 years ago

What is the chemical formula for ammonium hydroxide

hoa [83]

NH4OH is the answer. Hope this helps you.

8 0

3 years ago