When a star is in the main-sequence stage of its life, it is fusing __________ into _______

Why are the freezing points of water and the melting point the same

Sladkaya [172]

Because melting point and freezing point describe thesame transition of matter, in this case from liquid to solid (freezing) or equivalently, from solid to liquid (melting).

5 0

3 years ago

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You pull straight up on the string of a yo-yo with a force 0.35 N, and while your hand is moving up a distance 0.16 m, the yo-yo

jarptica [38.1K]

Answer:

a) 0.138J

b) 3.58m/S

c) (1.52J)(I)

Explanation:

a) to find the increase in the translational kinetic energy you can use the relation

$\Delta E_k=W=W_g-W_p$

where Wp is the work done by the person and Wg is the work done by the gravitational force

By replacing Wp=Fh1 and Wg=mgh2, being h1 the distance of the motion of the hand and h2 the distance of the yo-yo, m is the mass of the yo-yo, then you obtain:

$Wp=(0.35N)(0.16m)=0.056J\\\\Wg=(0.062kg)(9.8\frac{m}{s^2})(0.32m)=0.19J\\\\\Delta E_k=W=0.19J-0.056J=0.138J$

the change in the translational kinetic energy is 0.138J

b) the new speed of the yo-yo is obtained by using the previous result and the formula for the kinetic energy of an object:

$\Delta E_k=\frac{1}{2}mv_f^2-\frac{1}{2}mv_o^2$

where vf is the final speed, vo is the initial speed. By doing vf the subject of the formula and replacing you get:

$v_f=\sqrt{\frac{2}{m}}\sqrt{\Delta E_k+(1/2)mv_o^2}\\\\v_f=\sqrt{\frac{2}{0.062kg}}\sqrt{0.138J+1/2(0.062kg)(2.9m/s)^2}=3.58\frac{m}{s}$

the new speed is 3.58m/s

c) in this case what you can compute is the quotient between the initial rotational energy and the final rotational energy

$\frac{E_{fr}}{E_{fr}}=\frac{1/2I\omega_f^2}{1/2I\omega_o^2}=\frac{\omega_f^2}{\omega_o^2}\\\\\omega_f=\frac{v_f}{r}\\\\\omega_o=\frac{v_o}{r}\\\\\frac{E_{fr}}{E_{fr}}=\frac{v_f^2}{v_o^2}=\frac{(3.58m/s)}{(2.9m/s)^2}=1.52J$

hence, the change in Er is about 1.52J times the initial rotational energy

5 0

3 years ago

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Pls help! What is the average speed of an airplane that travels from New York to Los Angeles, a total distance of 4800 km, in 6.

Goshia [24]

Answer:

800 meters per hour

Explanation:

800 meters per hour is the average speed of an airplane that travels from New York to Los Angeles, a total distance of 4800 km, in 6.0 hours.

3 0

2 years ago

What happens when you sit in a chair?

stellarik [79]

B Yea that should be the right answer

3 0

3 years ago

A sound wave has a frequency of 500 Hz and a wavelength of 1.8 m. What is the wave speed of the sound wave? Question 1 options:

antoniya [11.8K]

Answer:

The wave speed of the sound wave is 900 $\frac{m}{s}$ .

Explanation:

Wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

Frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).

The propagation velocity is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave disturbance propagates along its displacement. Relate the wavelength (λ) and the frequency (f) inversely proportional using the following equation: v = f * λ.

In this case:

f= 500 Hz
λ= 1.8 m

Replacing:

v= 500 Hz* 1.8 m

v= 900 $\frac{m}{s}$

The wave speed of the sound wave is 900 $\frac{m}{s}$ .

7 0

3 years ago

When a star is in the main-sequence stage of its life, it is fusing __________ into ________

When a star is in the main-sequence stage of its life, it is fusing __ into