Which of the following is an example of a physical change? burning paper digesting food o ripping paper

Strong evidence for the existence of dark matter comes from observations of

adoni [48]

Answer:

NASA's Chandra X-ray Observatory and other telescopes such as the Hubble telescope.

Explanation:

Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies.

The above observations have provided the strongest evidence yet that most of the matter in the universe is dark.

5 0

3 years ago

g A ball thrown straight up into the air is found to be moving at 7.94 m/s after falling 2.72 m below its release point. Find th

kati45 [8]

The ball has height y and velocity v at time t according to

y = v₀ t - 1/2 g t ²

and

v = v₀ - g t

where v₀ is its initial speed and g = 9.80 m/s² is the magnitude of the acceleration due to gravity.

The ball is falling with a velocity of 7.94 m/s when it's 2.72 m below the release point, which at time t such that

-2.72 m = v₀ t - 1/2 g t ²

-7.94 m/s = v₀ - g t

Solve for t in the second equation:

t = (v₀ + 7.94 m/s)/g

Substitute this into the first equation and solve for v₀ :

-2.72 m = v₀ (v₀ + 7.94 m/s) /g - 1/2 g ((v₀ + 7.94 m/s)/g)²

-2.72 m = v₀²/g + (7.94 m/s) v₀/g - 1/2 (v₀ + 7.94 m/s)²/g

2 (-2.72 m) g = 2v₀² + 2 (7.94 m/s) v₀ - (v₀ + 7.94 m/s)²

2 (-2.72 m) (9.80 m/s²) = 2v₀² + (15.9 m/s) v₀ - (v₀² + (15.9 m/s) v₀ + 63.0 m²/s²)

-53.3 m²/s² = v₀² - 63.0 m²/s²

v₀² = 9.73 m²/s²

v₀ = 3.12 m/s

3 0

3 years ago

How have the competing explanations' experiments on atoms affected the development of the atomic model?

olga2289 [7]

Answer

Competing explanations' experiments on atoms gave a perfect modal of an atom

Explanation

There is a long story of atom. Different scientist gave different theories related to atomic modal but no one individually gave a perfect modal they perfect each other work and finally we got a perfect modal of atom.

Here is a short story of atom

in 400 B.C.E, Democritus was the first philosopher who gave the concept of atom. He believes that everything is made up of tiny spheres and these spheres are known as atoms.

in 1803, Dalton said that atoms of an element are similar. For example all atoms of carbon are similar.

in 1904 J. J. Thomson proposed that atom is sphere in which positively charged matter is filled and electrons are randomly scattered in that positively charged matter.

in 1911, Rutherford gave the concept of nucleus he believed that at the center of atoms all positively charged particles are present and this center is known as nucleus. He said that negatively charge electrons revolves around the nucleus in particular orbit.

In 1913, Niels Bohr gave a new model he believes that atomic model is similar to planetary modal. He believed that the electrons in an atom revolves around the nucleus in sets of orbits in a similar manner like the planets revolves around the sun.

In 1919, Rutherford gave the concept of proton.

In 1932, James Chadwick gives the concept of neutron.

In this way different scientist gave different theories related to atoms and finally they all gave a perfect modal of atom.

3 0

3 years ago

A monkey (mass m) is swinging on a vine of length L while carrying a bunch of bananas (a large bunch, mass m/2). His swinging mo

dmitriy555 [2]

Answer:

Explanation:

The period of oscillation will remain unchanged because the period of oscillation of a pendulum does not depend upon the mass of the bob . Here monkey along with bunch of banana represents bob .

When the monkey and banana were at height h /2 , they have potential energy as well as kinetic energy . banana is separated from the system . It carried its total energy along with it . But the energy of monkey remained intact with it . So it will keep on moving as usual . So it will attain the same maximum height as before .

Hence the amplitude of oscillation too will remain unchanged .

6 0

3 years ago

In mammals, the weight of the heart is approximately 0.5% of the total body weight. Write a linear model that gives the heart we

hammer [34]

Answer:

1201 lbs

Explanation:

Given that in mammals, the weight of the heart is approximately 0.5% of the total body weight.

Let the weight of the heart of a mammal be H

And the weight of the total body be B

The linear model that can gives the heart weight in terms of the total body weight will be:

H = 0.005B

B.) To find the weight of the heart of a whale whose weight is 2.402 × 105 lbs, substitute the whole weight in the formula.

H = 0.005 × 2.402 × 10^5

H = 1201 lbs

Therefore, the weight of the heart of the whale is 1201 lbs

8 0

3 years ago

Which of the following is an example of a physical change? burning paper digesting food o ripping paper​

Which of the following is an example of a physical change? burning paper digesting food o ripping paper