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2 years ago

Which statements describe properties of stars? Check all that apply.

2 answers:

7 0

One, three and five are correct.

Although if the second statement is saying that stars use gravitational force to support nuclear fusion which in turn produces energy then that would be correct, but I don’t think so :)

swat322 years ago

4 0

Answer:

Stars produce energy through nuclear fusion.
Stars are massive objects composed of gas.
Stars are composed primarily of hydrogen and helium.

Explanation:

Stars are massive objects that have a large gravitational field, which drives the star to contract on itself, which is why fusion occurs: in the center of the star the nuclei of atoms are already so close due to gravity and high temperatures that bind. This is what is called nuclear fusion and is the energy source of a star.

On the other hand yes, the main elements of a star are hydrogen and helium (two hydrogen nuclei fuse to make helium), this makes the star mainly a huge ball of gas so there is no solid surface where you can stand on.

And about water on a star, that is not possible. Temperatures on stars are very vey high that watter could not exist in a liquid form on them.

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Explain why the types of technology valued can vary.

Elan Coil [88]

Over time, the types of technology can vary and be improved upon so that more advanced techniques become more valued. This could be the situation with mining whereby back in the 1500's in underground mines the rock was broken by fire setting ie lighting a fire below the rock face to heat up the rock and then throwing cold water on it to crack it, so that it could be dug by hand. With the advent of explosives, this all changed so that the rock could be blasted. The increase in advance rates for an underground heading have thus gone from 5-20 feet per month to up to 300meters (984 ft) per month for a 24/7 mining operation, which is a huge improvement.

4 0

3 years ago

Read 2 more answers

A roller coaster cart of mass m = 223 kg starts stationary at point A, where h1 = 26.8 m and a while later is at B, were h2 = 14

Tresset [83]

Answer:

vB = 15.4 m/s

Explanation:

Principle of conservation of energy:

Because there is no friction the mechanical energy is conserve

ΔE = 0

ΔE : mechanical energy change (J)

K : Kinetic energy (J)

U: Potential energy (J)

K = (1/2)mv²

U = m*g*h

Where :

m: mass (kg)

v : speed (m/s)

h : hight (m)

Ef - Ei = 0

(K+U)final - (K+U)initial =0

(K+U)final = (K+U)initial

((1/2)mv²+m*g*h)final = ((1/2)mv²+m*g*h)initial , We divided by m both sides of the equation:

((1/2)vB² + g*hB = (1/2 )vA²+ g*hA

(1/2) (vB)² + (9.8)*(14.7) = 0 + (9.8)(26.8 )

(1/2) (vB)² = (9.8)(26.8 ) - (9.8)*(14.7)

(vB)² = (2)(9.8)(26.8 - 14.7)

(vB)² = 237.16

$v_{B} = \sqrt{237.16}$

vB = 15.4 m/s : speed of the cart at B

4 0

2 years ago

two horses pull against a rope with forces of 100 newtons in opposite directions. this is an example of

statuscvo [17]

It is an example of balanced force.

hope this helps. good luck

4 0

2 years ago

Read 2 more answers

Design an experimental set up to show that white light is made up of different colours of light

DaniilM [7]

Answer:

Issac Newton was the first to use a glass prism to obtain the spectrum of sunlight. He tried to split the colours of the spectrum of white light further by using another similar prism. However, he could not get any more colours. He then placed a second identical prism in an inverted position with respect to the first as shown.

This allowed all the colours of the spectrum to pass through the second prism. He found a beam of white light emerging from the other side of the second prism. This observation gave Newton the idea that the sunlight is made-up of seven colours.

Explanation:

6 0

2 years ago

Two spectators at a soccer game in Montjuic Stadium see, and a moment later hear, the ball being kicked on the playing field. Th

Akimi4 [234]

Answer:

a) The distance of spectator A to the player is 79.2 m

b) The distance of spectator B to the player is 43.9 m

c) The distance between the two spectators is 90.6 m

Explanation:

a) Knowing the time it takes the sound to reach both spectators, we can calculate their position relative to the player, using this equation:

x = v * t

where:

x = position of the spectators

v = speed of sound

t = time

Then, the position for spectator A relative to the player is:

x = 343 m/s * 0.231 s = 79.2 m

b)For spectator B:

x = 343 m/s * 0.128 s

x = 43.9 m

The distance of spectator A and B to the player is 79.2 m and 43.9 m respectively.

c) To calculate the distance between the spectators, please see the attached figure. Notice that the distance between the spectators is the hypotenuse of the triangle formed by the sightline of both. We already know the longitude of the two sides. Then, using Pythagoras theorem:

(Distance AB)² = A² + B²

(Distance AB)² = (79.2 m)² + (43.9 m)²

Distance AB = 90. 6 m

6 0

3 years ago