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3 years ago

Which of the following is a physical change?

2 answers:

4 0

A physical change is when the natural state of an object has or will be changed. Out of the following choices, sawing a piece of wood in half will be the physical change.

Credit for the answer explanation: oopsydaisy

NOTE: THIS ANSWER IS NOT MY ANSWER, BUT I HAVE CONFIRMED THAT IT IS CORRECT.

gladu [14]3 years ago

3 0

The answer would be A

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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

Which of the following is the best thermal insulator?

Vera_Pavlovna [14]

B. Aluminum is possibly correct

4 0

3 years ago

Two children ride side-by-side on a carousel. Their paths are shown in the image below.

Sonbull [250]

Answer:

The child represented by a star on the outside path.

Explanation:

5 0

3 years ago

Por qué se celebra el día del deporte

yulyashka [42]

Answer:

Día Internacional del Deporte para el Desarrollo y la Paz, 6 de abril. El deporte ha desempeñado históricamente un papel importante en todas las sociedades, ya sea en forma de competiciones deportivas, de actividades físicas o de juegos. ... De hecho, el deporte es un socio natural para el sistema de la ONU.

Explanation:

7 0

3 years ago

A diver can change his rotational inertia by drawing his arms andlegs close to his body in the tuck position. After he leaves th

NeX [460]

Answer:

3.14946 rad/s

Explanation:

$I_i$ = Intial moment of inertia

$I_f$ = Final moment of inertia

$\omega_i$ = Initial angular velocity

$\omega_f$ = Final angular velocity = $\dfrac{2}{1.33}\times 2\pi\ rad/s$

$\dfrac{I_f}{I_i}=\dfrac{1}{3}$

In this system the angular momentum is conserved

$L_i=L_f\\\Rightarrow I_i\omega_i=I_f\omega_f\\\Rightarrow \omega_i=\dfrac{I_f\omega_f}{I_i}\\\Rightarrow \omega_i=\dfrac{1\times \dfrac{2}{1.33}\times 2\pi}{3}\\\Rightarrow \omega_i=3.14946\ rad/s$

The angular velocity when the diver left the board is 3.14946 rad/s

3 0

3 years ago