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3 years ago

What holds the stars together in their galaxies? A. light B. orbits of the planets C. weight D. gravity

Physics

2 answers:

RUDIKE [14]3 years ago

8 0

It's D. Gravity holds everything in place

MaRussiya [10]3 years ago

3 0

Answer:

Explanation:

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Two straight wires are in parallel and carry electrical currents in opposite directions with the same magnitude of 2.0A. The dis

Veronika [31]

Answer:

Explanation:

Two straight wires

Have current in opposite direction

i1=i2=i=2Amps

Distance between two wires

r=5mm=0.005m

Length of one wire is ∞

Length of second wire is 0.3m

Force between the wire,

The force between two parallel currents I1 and I2, separated by a distance r, has a magnitude per unit length given by

F/l = μoi1i2/2πr

F/l=μoi²/2πr

μo=4π×10^-7 H/m

The force is attractive if the currents are in the same direction, repulsive if they are in opposite directions.

F/l = μoi1i2/2πr

F/0.3=4π×10^-7×2²/2π•0.005

F/0.3=1.6×10^-4

Cross multiply

F=1.6×10^-4×0.3

F=4.8×10^-5N

3 0

3 years ago

What changes must be done to the wire to increase its conductance.

777dan777 [17]

Answer:

- Decreasing the resistance

- Using a shorter length

- Using a smaller area wire

Explanation:

Formula for conductance in wires is;

G = 1/R

Where;

G is conductance

R is resistance

This means that increasing the resistance leads to a larger denominator and thus a smaller conductance but to decrease the denominator means larger conductance.

Thus, to increase the conductance, we have to decrease the resistance.

Resistance here has a formula of;

R = ρL/A

Where;

ρ is resistivity

L is length of wire

A is area

Thus, to decrease the resistance, we will have to use a shorter length and smaller area of wire.

8 0

3 years ago

Plaskett's binary system consists of two stars that revolve in a circular orbit about a center of mass midway between them. This

vova2212 [387]

Answer:

$1.554\times 10^{32}\ \text{kg}$

Explanation:

M = Mass of each star

T = Time period = 15.5 days

v = Orbital velocity = 230 km/s

G = Gravitational constant = $6.674\times 10^{-11}\ \text{Nm}^2/\text{kg}^2$

Radius of orbit is given by

$R=\dfrac{vT}{2\pi}$

We have the relation

$\dfrac{Mv^2}{R}=\dfrac{GM^2}{(2R)^2}\\\Rightarrow M=\dfrac{4Rv^2}{G}\\\Rightarrow M=\dfrac{4\dfrac{vT}{2\pi}v^2}{G}\\\Rightarrow M=\dfrac{2v^3T}{\pi G}\\\Rightarrow M=\dfrac{2\times 230000^3\times 15.5\times 24\times 60\times 60}{\pi\times 6.674\times 10^{-11}}\\\Rightarrow M=1.554\times 10^{32}\ \text{kg}$

The mass of each star is $1.554\times 10^{32}\ \text{kg}$

6 0

3 years ago

Taylor mixes two liquids together in a beaker. A solid forms at the bottom of the beaker, and the liquid changes from pink to bl

Dimas [21]

It is a chemical change and a physical change

3 0

3 years ago

A jeweler is determining the optical properties of an unknown blue gemstone. She uses an angle of incidence of 62°, and measures

Juliette [100K]

Answer:

n = 1.76

Explanation:

According to the rule of ( n1 sin theta1 = n2 sin theta2 )

we know both angles so we insert them to the law and apply n1 = 1

so 1/2 = n2 sin 62 and we get the final answer

3 0

4 years ago