Answer:
the radiation pressure that has to push the star
Explanation:
In the stars there are two forces that act in the opposite direction.
- On the one hand there is the force of gravity that the star has to collapse
- On the other is the radiation pressure that has to push the star. This pressure comes from the radiation and velocity of the particles involved in nuclear reactions.
An object rotates describing a horizontal circumference when subjected to a centripetal force F. What centripetal force will act on the object if the radius of the circle is doubled and the kinetic energy of the object is halved? A) F/4 B) F/2 C) F D) 4F please explain this to me : (
Answer:
Option A: F/4
Explanation:
Centripetal force, [tex]F = \frac{mv^{2} }{r}[/tex]
Where v = speed
r = radius
Since Kinetic Energy, [tex]E_{k} = 0.5 mv^{2}[/tex]
Writing centripetal force in terms of kinetic energy, [tex]F = \frac{2 E_k}{r}[/tex]
If the initial radius of the circle, r₁ =r
The doubled radius, r₂ = 2r
If the initial kinetic energy, [tex]KE_1 = E_{k}[/tex]
The halved kinetic energy, [tex]KE_2 = 0.5E_{k}[/tex]
Therefore, the new Centripetal force becomes:
[tex]F_{2} = \frac{2(0.5 E_k)}{2r} \\F_{2} = \frac{0.5 E_k}{r}\\F_{2} =\frac{1}{4} * \frac{2 E_k}{r}\\Since, F = \frac{2 E_k}{r} \\F_{2} =\frac{1}{4} * F\\F_{2} =\frac{F}{4}[/tex]
A rubber band that has been stretched has gained ____ energy
OA) heat
OB) kinetic
OC) potential
D) chemical
Answer: potential
Explanation:
In a hydroelectric power station, how much potential energy is lost by 100tonnes of water flowing down through the pipes, falling a vertical distance of 200metres? [1tonne=1000kg.]
Answer:
196000000 J
Explanation:
Potential Energy: This can be defined as the energy of a body due to its position in the gravitational field.
From the question,
P.E = mgh.................. Equation 1
Where P.E = potential Energy, m = mass of the water, h = height, g = acceleration due to gravity.
Given: m = 100 tonnes = (100×1000) = 100000 kg, h = 200 m
Constant: g = 9.8 m/s²
Substitute into equation 1
P.E = 100000(200)(9.8)
P.E = 196000000 J.
Note: When a object falls through a height he losses its potential energy.
Hence the potential energy lost = 196000000 J = 196 MJ.
Is a 5kg ball is rolling to the right and has a velocity of 4 m/s what is the momentum of the ball
Answer:
∆p = 20 kg * m/s
Explanation:
The change in momentum is the mass of the body multiplied by the change in its velocity.
In formula form ∆p = m * ( ∆v ).
with m = 5 kg and ∆v = 4 m/s
∆p = 5 kg * 4 m/s
∆p = 20 kg * m/s
A wire having resistance 20 ohm is bent to make a closed square.What is the resistance across the diagonal of square?
Answer:
5 Ω
Explanation:
When it is bent into a square, each side of the square will get 5 Ω resistance. As considered diagonally ,path of the wire between to diagonal points is the two sides of the square (that is half the length of the wire connected in parallel position). Which gives 10 ohm parallel to 10 ohm wire. So it finally read as 5 Ω wire
A train is moving west with an initial velocity of 20m/s accelerates at 4m/s for 10 seconds during this time the train moves a distance
Answer:
400m
Explanation:
From Newton's law of motion;
S = ut + 1/2 at2
Where U is initial velocity
a is acceleration
t is velocity hence;
S is distance covered
S = 20×10 + 1/2 × 4×(10)^2
= 200 + 200 = 400m
The power of a machine is 6000 W. This machine is scheduled for design improvements. Engineers have reduced the
time for the output by one half from 15 s to 7.5 s. What work would be required to cut the time in half.
Step #1
Step #2
Step #3
Explanation:
Work = power × time
W = (6000 W) (7.5 s)
W = 45,000 J
Concrete and steel expand to almost the same amount when they are heated. Explain why you think this is lucky?
Answer:
While making a bridge or a building, the first thing that comes to our mind is that these are always made by the combination of concrete and steel. Concrete is cheap, but it has the property of breaking when it is twisted or under tension. Steel is expensive, If we made the whole thing with it, it will cost a lot. To provide strength under a reasonable cost, we use the combination of concrete and steel. Another postive point which they have together is that they both expand equally under heat, because they have the same coefficient of thermal expansion. It proves really useful, because if they had different coefficients of thermal expansions, one would expand more than the other, which will create tensions in the mixture and would break it easily. In the case, many cracks would start to appear in the bridge or buildings, which will eventually break them.
What are some advantages
and disadvantages to using
superconductors as electric
transmission lines
Answer:
Insulators show very high resistance to electricity. Conductors like copper show some resistance. Another class of materials show no resistance at all when cooled to very low temperatures, cooler than the coolest deep freezer. Called superconductors, they were discovered in 1911.
Explanation: i looked it up
An astronaut is moving in space when a big explosion occurs about 50 meters behind him. How will the astronaut come to know about the explosion?
Choose:--
From the sound of the explosion
From the light due to the explosion
From light and sound due to the explosion
From the vibrations due to the explosion
Answer:
The correct answer is B.
The astronaut will know due to the light from the explosion.
Explanation:
Sound and vibrations require a medium such as air to travel through. Space, there is no air. Only a vacuum. So sound and vibrations are unable to travel. Light requires no medium to travel. It can go through a vacuum.
Therefore the Astronaut will see a bright flash of light as it travels from the explosion to outer space. It is also important to note that light can travel very far because nothing else interacts with its wave particles and as such, it cannot be impeded.
Cheers!
what is the wavelength of radio waves transmitted by an FM station at 90MHz where 1M=10^6, and speed of radiowave is 3*10^8m/s
Answer:
λ = 3.33 m
Explanation:
Given:
Frequency = f = 9 × 10⁷ Hz
Speed = v = 3 × 10⁸ m/s
Required:
Wavelength = λ = ?
Formula:
v = fλ
Solution:
Putting the givens in the formula
v = fλ
λ = [tex]\frac{v}{f}[/tex]
λ = [tex]\frac{3*10^8}{9*10^7}[/tex]
λ = 0.33 × 10¹
λ = 3.33 m
state the principle of conservation of energy
Answer:
Principal of Conservation of Energy states that " Energy is neither created nor destroyed. However, It is just converted to other forms of energy"
A water distiller which is used to purify water. The distiller boils water and then condenses most of the water vapour back to water. (a) The water distiller is filled with 5.0 kg of water at 20 °C The specific heat capacity of water = 4 200 J/Kg °C Calculate the energy needed to raise the temperature of the water to 100 °C ___________________________________________________________________
Answer:
Energy needed 1680kJExplanation:
The quantity of heat required to raise the temperature of water to 100 degrees is expressed as
[tex]Q= mc(T2-T1)[/tex]
Given data
mass of water = 5kg
initial temperature T1= 20 °C
final temperature T2= 100 °C
Specific heat capacity of water= 4 200 J/Kg °C
[tex]Q= 5* 4 200(100-20)\\Q= 21000(80)\\Q= 1680000\\Q= 1680kJ[/tex]
4. ____________ occurs when one object slides over another.
a. Sliding friction
b. Static friction
c. Rolling friction
d. Net force
Answer:
A. Sliding friction
Explanation:
Sliding friction is weaker than static friction
Answer:
Rolling Friction
Explanation:
I know this because the definition of rolling friction is : type of friction that happens when one body rolls over another
Calculate the weight of an object on earth surface having 600km from surface of earth?
Your question seems to contradict itself. You said "on Earth surface" and then you said "600 km from surface of the Earth" ... both in the same sentence.
I'll assume that the object is actually 600 km from surface of the Earth, because that makes the question (and the answer) more interesting.
We know that the weight of any object is (mass) x (gravity). Those are the two numbers we need in order to calculate the object's weight. Mysteriously, you haven't told us either one. We'll call the object's mass ' M ' (clever, eh ?), and we'll calculate the value of gravity up there where the object is located.
We now that the acceleration of gravity is inversely proportional to the square of the distance between the centers of two objects. When an object is on the Earth's surface, it's 6,371 km from Earth's center, and the acceleration of gravity there is 9.8 m/s².
The object in the question is 600 km farther from Earth's center, so the acceleration of gravity there is
(9.8 m/s²) · (6371 / 6971)² = 8.2 m/s².
So the object's weight is (8.2 M) Newtons.
This is about 84% of its weight on Earth's surface.
(Notice that the astronauts aboard the International Space Station are NOT "weightless". The strength of gravity up there where they are is around 84% of what it is down on the ground. The question of why they float, and why their muscles waste away, is a topic for another Brainly question.)
What is the most likely reason why these early flowers gradually changed to many different types of flowers over time?
Answer:
The flowers adapted to environmental conditions.
Explanation:
Calculate the transfer of energy by a force of 15N when it moves the object by a distance of 5m
a. In the direction of the force
b. In a direction at 60° to the direction of the force
c. At right angles to the force
NEED EXPLAINATION
Answer:
a) 75 J
b) 37.5 J
c) 0
Explanation:
Work is the force exerted on an object causing it to move, Work is the product of force and displacement. Work is not done if the force and displacement are at right angles to each other. It is given by:
[tex]Work(energy)=Fxcos(\theta)[/tex]
F is the force, x is the displacement and Θ is the angle between force and displacement.
a) Force (F) = 15N and distance (x) = 5. Since it is in the direction of the force, Θ = 0
[tex]Work(energy)=Fxcos(\theta)= 15*5*cos(0)=75J[/tex]
b) Force (F) = 15N and distance (x) = 5. Θ = 60
[tex]Work(energy)=Fxcos(\theta)= 15*5*cos(60)=37.5J[/tex]
c) Force (F) = 15N and distance (x) = 5. Θ = 90
[tex]Work(energy)=Fxcos(\theta)= 15*5*cos(90)=0[/tex]
A sheet of paper 3.0 cm by 4.0 cm is lying on the desk. If the atmospheric pressure is 1.013105 Pa, what is the total force exerted on the top side of the paper by the atmosphere?
Answer:
132.56N
Explanation:
Pressure is defined as force per unit area.
Expressed mathematically as;
P = F/A
Where P-pressure
F-force
A-area
From the above formula,
F= P×A
= 1.1013 × 10^5 × (3×4/10000)
= 11.013×12 =132.56N
Note: the unit of measure in cm is converted to m and since 100cm makes 1m for each sides 3cm and 4cm we convert to 'm' by dividing by 100 twice giving division by 10000)
The unit of measure Pa means Pascal and is the same as N/m2
The object will feel minimum force of gravity at the
Answer:
space , small amount of gravity is found in the space ,infact we can say that there is no gravity in the space
Answer:
Poles
Explanation:
The gravitational force is maximum at the equator and minimum at the poles.
Which objects would sink in honey, which has a density of 1.4 g/cm³? Check all that apply.
Answer:
any object that has density more than 1.4
Explanation:
The object that has density more than 1.4 is denser than the honey
a 50.0kg bicyclist on a 10.0kg bicycle speeds up from a 5.00m/s to 10.0m/s
Answer:
The total kinetic energy before accelerating = 750 JThe total kinetic energy after accelerating = 3,000 JTotal work done = 2,250 JExplanation:
Given:
Mass of bicyclist = 50 kg
Mass of bicycle = 10 kg
Initial velocity (u) = 5 m/s
Final velocity (v) = 10 m/s
Find:
(a) What was the total kinetic energy before accelerating = ?
(b) What was the total kinetic energy after accelerating = ?
(c) How much work was done to increase the kinetic energy of the bicyclist = ?
Computation:
Total mass (M) = 50 kg + 10 kg = 60 kg
1. The total kinetic energy before accelerating = 1/2[Mu²]
The total kinetic energy before accelerating = 0.5[(60)(5)²]
The total kinetic energy before accelerating = 750 J
2. The total kinetic energy after accelerating = 1/2[Mv²]
The total kinetic energy after accelerating = 0.5[(60)(10)²]
The total kinetic energy after accelerating = 3,000 J
3. Total work done = Δ K.E
Total work done = 3,000 J - 750 J
Total work done = 2,250 J
Which force does not operate at a distance of 1 m?
A. Weak nuclear
O B. Electric
C. Gravitational
D. Magnetic
Answer:
A
Explanation:
Assume that a machine puts out 8000 joules of work when the user puts in 10,000 joules of work. What is the efficiency of the machine?
Answer:
80 Percent
Explanation:
E=energy output/energy input×100
E=8000/10000×100
E=0.8×100
E=80 percent.
Mark brianliest if my answer suit your question
If the machine put, in 8000 J, and the user puts 10,000 J of work then the efficiency of the machine will be equal to 80%.
What is Work?Work is a physics term used to describe the transfer of energy that takes place when an object changes above a distance because of an external force, at least some of which is given in the vector of the dislocation. The element of the force acting all along the path multiplied by the length of the path can be used to calculate work if the force is constant.
Mathematically, this idea is expressed as W = fd, where W is the effort and f is the force multiplied by d, the distance. Work is completed whenever the force is applied at an angle with about the displacement.
As per the data provided in the question,
Total input energy = 10,000 J
Total output energy = 8,000 J
Then, the efficiency (η) of the machine will be,
η = (output energy/input energy) × 100
η = 8000/10000 × 100
η = 80%.
To know more about Work:
https://brainly.com/question/13662169
#SPJ2
A 2kg object is dropped from a height 10m.Calculate the speed of the object after it has fallen 5m, assuming there is no resistance. g= 10 N/kg
Answer:
10m/s
Explanation:
[tex]d=v_ot+\dfrac{1}{2}at^2[/tex]
Since there is no initial velocity as the object is dropped, you can write the following equation:
[tex]5=\dfrac{1}{2}(10)t^2 \\\\1=t^2 \\\\t=1[/tex]
Now that you know how long the fall took, you can use another physics equation to find the velocity at that point.
[tex]v_f=v_o+at[/tex]
Since there once again is no initial velocity, you can rewrite this as:
[tex]v_f=at=(10)(1)=10m/s[/tex]
Hope this helps!
The kinetic energy the object has at any point during the fall is exactly the potential energy it lost by falling to that height.
Potential energy = (mass) · (gravity) · (height)
Change of potential energy = (mass) · (gravity) · (change of height)
Change of potential energy = (2 kg) · (10 m/s ) · (-5 m)
Change of potential energy = 100 Joules
Kinetic energy = (1/2) · (mass) · (speed²)
Kinetic energy = (1 kg) · (speed² )
100 J = (1 kg) · (speed²)
Speed² = (100 J) / (1 kg)
Speed² = (100 kg-m²/s²) / (1 kg)
Speed² = (100 m²/s²)
Speed = 10 m/s
explain the causes of yaa asantewaa war of 1900
Answer: the conflict began when a british representative - Sr. Frederick Mitchell Hodgson sat on the golden stool.
Explanation:
since the stool wasn't a throne, when Yaa Asantewaa found out, he led a rebellion which killed 1000 British and allied African soldiers and 2,000 Ashanti.
good luck with your assignment :)
A) Is it possible for an object that, object with zero acceleration have velocity? If yes give an example if not give its proof.
Answer:
Yes, in case of uniform velocity
Explanation:
This is the case of uniform velocity. If a body covers equal displacement in equal intervals of time, then the velocity of a body is said to be ‘Uniform Velocity’. It meas that the velocity of a body remains constant during the motion and it does not change.
Since, acceleration is defined as the rate of change of velocity.
Therefore, if there is no change in velocity or in other words the change in velocity is zero, then the acceleration is also zero.
a = ΔV/t = 0/t
a = 0 m/s²
So, the acceleration of the body is 0 m/s², but it has a uniform velocity
Hence, it is possible for an object that, object with zero acceleration have velocity, which is the case case of uniform velocity.
When the kinetic energy of particles in a substance decreases, what also decreases?
93
The size of the particles in the substance.
The number of particles in the substance.
The substance's specific heat.
The substance's temperature.
Answer: D
The substance's temperature
Explanation:
According to kinetic theory, increase in temperature causes increase in kinetic energy of particles in a system.
When the kinetic energy of particles in a substance decreases, it has nothing to do with the size of the particles and the specific heat capacity of the particles or substance. But it a clear indication that the substance temperature has also decreased.
Answer:
D
Explanation:
The ________ of a particle for a given ‘Interval of time’ is defined as the ratio of total distance travelled to the total time taken.
uniform speed
average speed
uniform velocity
average velocity
Answer:
The average speed of a particle for a given ‘Interval of time’ is defined as the ratio of total distance travelled to the total time taken.
Explanation:
To find the average speed we take the total
distance traveled divided by the time interval.
Write down any four points that should be considered during household wiring
Answer:
USE RUBBER CLOVES
USE A PLIER
USE CONDUCTIVE WIRES
SWITHC OFF THE MAIN SWITCH WHILE WIRRING
Explanation:
An object with more mass has more kinetic energy than an object with less
mass, if both objects are moving
OA) at the same speed
OB) in the same direction
OC) in opposite directions
Explanation:
The kinetic energy of an object is given in terms of its mass and object as :
[tex]K=\dfrac{1}{2}mv^2[/tex]
An object with more mass has more kinetic energy. An object with less mass, if both objects are moving at the same speed, in opposite directions, will have less kinetic energy. The square of v will give positive number.
