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3 years ago

I THINK I KNOW THE ANSWER BUT I NEED VERIFICATION!!!!!!!

2 answers:

4 0

Yes, the answer is in fact C. All of the above.

Variable stars are stars that change in brightness. The change could be due to the physical change in the star or it could also be caused when another star crosses another, or in other words eclipse.

Umnica [9.8K]3 years ago

4 0

The answer is All of the above. Variable Stars include White Dwarf Stars, Red Giant Stars & Binary Stars. A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. A red giant star is a dying star in the last stages of stellar evolution. Binary stars are two stars orbiting a common center of mass. The brighter star is officially classified as the primary star, while the dimmer of the two is the secondary .

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A single mass (m1 = 3.5 kg) hangs from a spring in a motionless elevator. The spring constant is k = 278 N/m. 1)What is the dist

artcher [175]

<h2>Answer:</h2>

0.126m

<h2>Explanation:</h2>

According to Hooke's law, the force (F) acting on a spring to cause an extension or compression (e) is given by;

F = k x e -------------------(i)

Where;

k = the spring's constant.

From the question, the force acting on the spring is the weight(W) of the mass. i.e

F = W -----------------------(ii)

But;

W = m x g;

where;

m = mass of the object

g = acceleration due to gravity [usually taken as 10m/s²]

From equation (ii), it implies that;

F = W = m x g

Now substitute F = m x g into equation(i) as follows;

F = k x e

m x g = k x e ------------------(iii)

From the question;

m = m1 = 3.5kg

k = 278N/m

Substitute these values into equation (iii) as follows;

3.5 x 10 = 278 x e

35 = 278e

Now solve for e;

e = 35/278

e = 0.126m

Therefore, the distance the spring is stretched from its unstretched length (which is the same as the extension of the spring) is 0.126m

3 0

3 years ago

PLEASE ANSWER, I NEED HELP

Scorpion4ik [409]

1) The gravitational force between Ellen and the moon is $1.56\cdot 10^{-3} N$

2) The two forces are equal, while the acceleration of the bus is smaller than the acceleration of the bicycle.

Explanation:

The magnitude of the gravitational force between two objects is given by

$F=G\frac{m_1 m_2}{r^2}$

where

$G=6.67\cdot 10^{-11} m^3 kg^{-1}s^{-2}$ is the gravitational constant

$m_1, m_2$ are the masses of the two objects

r is the separation between them

In this problem, we have:

$m_1 = 47 kg$ is the mass of Ellen

$m_2 = 7.35\cdot 10^{22} kg$ is the mass of the moon

$r=3.84\cdot 10^8 m$ is the distance between Ellen and the moon

Substituting, we find the gravitational force between Ellen and the moon:

$F=(6.67\cdot 10^{-11})\frac{(47)(7.35\cdot 10^{22})}{(3.84\cdot 10^8)^2}=1.56\cdot 10^{-3} N$

We can analyze the forces acting in the collision between the bus and the bicycle by using Newton's third law of motion, which states that:

"When an object A exerts a force (called action) on an object B, then object B exerts an equal and opposite force (called reaction) on object A"

Applied to our problem, this means that the force exerted by the bus on the bicycle during the collision (action force) is equal (and opposite) to the force exerted by the bicycle on the bus (reaction force).

Now let's analyze the accelerations of the two vehicles. We can find the acceleration of each vehicle by using Newton's second law:

$a=\frac{F}{m}$

where

a is the acceleration

F is the force exerted on the vehicle

m is the mass of the vehicle

As we said previously, the force F exerted on each of the two vehicles: so, the acceleration only depends on the mass. In particular, the acceleration is inversely proportional to the mass: therefore, the larger the mass of the vehicle, the smaller the acceleration. This means that the acceleration of the bus is smaller than the acceleration of the bicycle.

Learn more about gravitational force:

brainly.com/question/1724648

brainly.com/question/12785992

And about Newton's third law:

brainly.com/question/11411375

#LearnwithBrainly

6 0

2 years ago

a hippopotamus produces a pressure of 250000 pa when it is standing on all four feet if the weight of the hippo is 40000 N what

mamaluj [8]

0.04m²

Explanation:

Given parameters:

Pressure = 250000Pa

Weight = 40000N

Unknown:

Area of each foot = ?

Solution:

Pressure is the force exerted per unit area of a body

Pressure = $\frac{force}{area}$

To find the area;

Area = $\frac{force }{pressure}$

Area = $\frac{40000}{250000}$ = 0.16m²

The force exerted by all the four feet is 0.16m²

the area of each feet = $\frac{0.16}{4}$ = 0.04m²

Learn more:

Pressure brainly.com/question/7139767

#learnwithBrainly

8 0

2 years ago

A child in a boat throws a 5.80-kg package out horizontally with a speed of 10.0 m/s. The mass of the child is 24.6kg and the ma

Sergio [31]

Answer:

-0.912 m/s

Explanation:

When the package is thrown out, momentum is conserved. The total momentum after is the same as the total momentum before, which is 0, since the boat was initially at rest.

$(m_c + m_b)v_b + m_pv_p = 0$

where $m_c = 24.6 kg, m_b = 39 kg, m_p = 5.8 kg$ are the mass of the child, the boat and the package, respectively. $, v_p = 10m/s, v_b$ are the velocity of the package and the boat after throwing.