PHYSICS COLLEGE

A star of uniform mass with a radius R rotates about its diameter with angular momentum L. Under the action of internal forces the star collapses until its radius is one fourth of its initial size. The magnitude of its new angular momentum is: L
16L
L/16
4L
L/4

Answers

Answer 1
Answer:

Answer:

L / 16

Explanation:

Mass = m, Radius = R, angular momentum = L

Now, new radius, R' = R/4, mass = m, angular momentum, L' = ?

By the law of conservation of angular momentum

If there is no external torque is applied, the angular momentum of the system remains conserved.

L = I x w

Moment of inertia I depends on the mass and the square of radius of the star.

If the radius is one fourth, the angular momentum becomes one sixteenth.

So, L' = L / 16


Related Questions

COLLEGE

Two forces and are applied to an object whose mass is 13.3 kg. The larger force is . When both forces point due east, the object's acceleration has a magnitude of 0.723 m/s2. However, when points due east and points due west, the acceleration is 0.493 m/s2, due east. Find (a) the magnitude of and (b) the magnitude of .

Answers

Answer:

Explanation:

First, It's important to remember F = ma, and in this problem m = 13.3 kg

This can be reduced to a simple system of equations problem.  Now if they are both going the same way then we add them, while if they are going the opposite way we subtract them.  So let's call them F1 and F2, with F1 arger than F2.  Now, When we add them together F1+F2 = (.723 m/s^2)*13.3kg and then when we subtract them, and have the larger one pushing toward the east, let's call F1 the larger one, F1-F2 = (.493 m/s^2)*13.3kg.  

Can you solve this system of equations seeing them like this, or do you need more help?

HIGH SCHOOL

Newton's 1st law of motion states that a moving object will go in a straight line unless an outside force changes this motion. What outside force prevents the planets from moving in a straight line into space? gravity
meteorite impacts
supernovas
nuclear fusion

Answers

The gravity of the sun is keeping all the planets in orbit

MIDDLE SCHOOL

Describe how Newton's laws of gravity and motion related to your observations and responses to the questions above in a 150 word paragraph.

Answers

Answer:

Explanation:

You probably know that the Earth pulls down on you. What you might not realize is that you are also pulling up on the Earth. For example, if the Earth is pulling down on you with a gravitational force of 500 N, you are also pulling up on the Earth with a gravitational force of 500 N. This remarkable fact is a consequence of Newton's third law. This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself. We sometimes refer to this law loosely as action-reaction, where the force exerted is the action and the force experienced as a consequence is the reaction. Other examples of Newton’s third law are easy to find. As a professor paces in front of a whiteboard, she exerts a force backward on the floor. The floor exerts a reaction force forward on the professor that causes her to accelerate forward.

MIDDLE SCHOOL

you are sitting behind the bus driver on a moving bus in relation to a person standing on the sidewalk you are what

Answers

You are sitting behind the bus driver on a moving bus in relation to a person standing on the sidewalk you are what

--------------------------

relative to sidewalk you are moving with the driver

MIDDLE SCHOOL

Both magnetism and electricity result from which fundamental force? A. Strong interaction
B. Weak interaction
C. Electromagnetic interactions
D. Gravitational interactions

Answers

Answer:

C. Electromagnetic interactions

Explanation:

All forces related to magnetism and charge is known as electromagnetic force.

as we know that the force between two charges is given by Coulomb's law which is given as

also we know that force on a moving charge is given as

so whenever there is force related to charge and magnet then it is considered as fundamental force given as

C. Electromagnetic interactions

COLLEGE

A boy pulls a 28.0-kg box with a 230-N force at 35° above a horizontal surface. If the coefficient of kinetic friction between the box and the horizontal surface is 0.24 and the box is pulled a distance of 30.0 m, what is the work done by the friction force on the box?

Answers

Answer:

1977.696 J

Explanation:

Given;

Weight of the box = 28.0 kg

Force applied by the boy = 230 N

angle between the horizontal and the force = 35°

Therefore,

the horizontal component of the force = 230 × cosθ

= 230 × cos 35°

= 188.405 N

Coefficient of kinetic friction, μ = 0.24

Force by friction, f = μN

here,

N = Normal force = Mass × acceleration due to gravity

or

N = 28 × 9.81 = 274.68 N

therefore,

f = 0.24 × 274.68

or

f = 65.9232 N

Now,

work done by the boy, W₁ = 188.405 N × Displacement  

= 188.405 N × 30

= 5652.15 J

and,

the

work done by the friction, W₂ = - 65.9232 N × Displacement  

= - 65.9232 N × 30 m

= - 1977.696 J

[ since the friction force acts opposite to the direction of motion, therefore the workdone will be negative]

HIGH SCHOOL

Calculate the answer. Express it in scientific notation. All answers should have the correct number of significant figures. (386) (204) =

Answers

Answer:

In scientific notation, a number is written between 1 and 10 multiplied by a power of 10.

where m lies between 1 and 10 and n is an integer.

So, 78744 can be written in scientific notation as :

Significant digits in the answer depends on the least significant digits in the multipliers. The significant digits in the multipliers is 3. Therefore, the answer must contain 3 significant digits.

Answer:


so we know that when you multiply it together it equals 78,744 so we move it back 4. which brings us to 7.87 then multiply it by 10^4 which is 44.

so the answer is 7.87 * 10^4

hope i was able to help plz message me if u need anymore help or if u dont quite understand.  

HIGH SCHOOL

A car is traveling at 20 meters/second and is brought to rest by applying brakes over a period of 4 seconds what is its average acceleration over this time interval?

Answers

Answer:

Acceleration of the car is

Explanation:

It is given that,

Initial speed of the car, u = 20 m/s

Finally, it brought to rest, v = 0

Time taken, t = 4 s

We need to find the average acceleration over this time interval. The acceleration of an object is given by following formula as :

         

So, the car is decelerating at . Hence, this is the required solution.

Avg. acceleration = -5 m/s^2.
MIDDLE SCHOOL

It takes much longer to bake a whole potato than potatoes that have been cut into pieces why ?

Answers

A whole potato must be cooked from outside in, just like a potato cut into slices.

however, with a potato cut into slices, there is a greater surface area, so there is more "outside" and less inside. as a result, the sliced potato cooks faster.
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