A block at a height of 50 meters having mass 5 kg is allowed to fall hits a bullet moving with a velocity of 300 meters per second & stucks into it at the mean position...what height can it attain now?
Regards,
farhan
Regards,
farhan
force between two charges
Q. One brass plate is inserted between 2 charges. The force between two charges will
a. remain same
b. increase
c. decrease
d. fluctuate
explain with reason
Regards,
Ayush Goyal
a. remain same
b. increase
c. decrease
d. fluctuate
explain with reason
Regards,
Ayush Goyal
Why 32 degree as ice point n 212 degree as steam point in fahrenheit scale?
what is the main reason for choosing 32 degree as ice point n 212 degree as steam point in fahrenheit scale?In celsius they refer to water, but what about here? similarly what about Reaumur scale?
Regards,
krishna
Regards,
krishna
Black Hole again
Hello,
I understand that because of time dilation that we could never see something actually entering a black hole. That is to say, from our earth view, time would appear to stop at or near the event horizon and observed objects would appear to move slower and slower until they seemed to be standing still (to be clear, I certainly understand that the object does not actually halt its motion, and will continue to accelerate and fall into the hole). I understand (laymans level) the basic concept of time dilation, and that it is how the speed of light remains constant for all observers, but the idea of something appearing to halt its motion is pretty mind-blowing...I picture (when it becomes technically possible to actually see one) an event horizon cluttered with incoming matter but that matter never desending (according to our observation) into the black hole. That seems far fetched to me, so I am sure I'm missing something.
By the way, I am in my sixties, and this question has vexed me to decades, so any light (time-dilated or not) that you can shed would be really appreciated!!
Al
Regards,
Alan Negin
I understand that because of time dilation that we could never see something actually entering a black hole. That is to say, from our earth view, time would appear to stop at or near the event horizon and observed objects would appear to move slower and slower until they seemed to be standing still (to be clear, I certainly understand that the object does not actually halt its motion, and will continue to accelerate and fall into the hole). I understand (laymans level) the basic concept of time dilation, and that it is how the speed of light remains constant for all observers, but the idea of something appearing to halt its motion is pretty mind-blowing...I picture (when it becomes technically possible to actually see one) an event horizon cluttered with incoming matter but that matter never desending (according to our observation) into the black hole. That seems far fetched to me, so I am sure I'm missing something.
By the way, I am in my sixties, and this question has vexed me to decades, so any light (time-dilated or not) that you can shed would be really appreciated!!
Al
Regards,
Alan Negin
Electrostatic Equilibrium
Two identical pith balls,each carrying a charge q,are suspended from a common point by two strings of equal length l.find the mass of each ball if the angle between them is 2x in equilibrium.
Regards,
Ayash Mohanty
Regards,
Ayash Mohanty
Alternating current frequency
if an alternating current of frequency 50 hz is flowing through a conducting wire then how many times the current becomes zero in 1 second
Asked Aniketh
Asked Aniketh
Image formed by a transparent sphere
A transparent sphere of radius R and refractive index of u is kept in air. At what distance from the surface of sphere should a point object be placed so as to form real image at same distance from sphere?
Regards,
shivendu
[R / (u-1)] - R
Try yourself with lensmakers formula
The optic centre is at the centre of the sphere. SO the surface is already at a distance R from the optic centre.
Regards,
shivendu
[R / (u-1)] - R
Try yourself with lensmakers formula
The optic centre is at the centre of the sphere. SO the surface is already at a distance R from the optic centre.
Defying Gravity?!
I have once come across a materiel / substance / compound / or something that keeps objects cut off from the earth's gravitational pull. In other words this will keep the object suspended in the air and will not allow it to touch the ground. Hence we can say that this is a barrier between the object and the earth's gravity. Can you please give me the name of this material / substance / compound / gas / or what ever it is?
Regards,
Parveen
Magnetic levitation is one phenomenon which can do this.
Regards,
Parveen
Magnetic levitation is one phenomenon which can do this.
Impulse
A Hammer weighing 3kg strikes the head of a nail with a speed of 2m/s and drives it by 1cm into the wall. find the impulse?
Asked Sree
Impulse is the product of force an time. Impulse of a force is also equal to the change in momentum produce. (Impulse Momentum Principle)
Here change in momentum is equal to 3kg x 2m/s = 6 kg m/s.
(if we assume that the hammer does not bounce off after striking the nail)
Asked Sree
Impulse is the product of force an time. Impulse of a force is also equal to the change in momentum produce. (Impulse Momentum Principle)
Here change in momentum is equal to 3kg x 2m/s = 6 kg m/s.
(if we assume that the hammer does not bounce off after striking the nail)
Is acceleration have a scalar quantity. if not why?
Acceleration is a vector quantity and therefore acceleration due to gravity too is vector.
Acceleration due to gravity has magnitude as well as direction. The direction of acceleration due to gravity is towards the centre of earth.
Acceleration due to gravity has magnitude as well as direction. The direction of acceleration due to gravity is towards the centre of earth.
Don't get confused! We are not PSYCHICS .. it's Physics here....!
We get many questions here which are intended to be asked to a psychic reader. But we are not those. We deal with Physics here ... often referred to as the true science explaining the various natural phenomena using cause effect relationship and more.
Sound distance speed
1. A man while beating a drum at the rate 5 per second walks toward a cliff till echo of beating dissappears completely. He walks at the rate of 8 km/hr. Calculate the distance of man from cliff in the beginning if he walked for 5 minute(Velocity of sound in air=350m/s).
2. A source emitting sound of frequency 180 Hz is placed in front of a wall at a distance of 2m from it. A detector is also placed in front of the wall at the same distance from it. Find the minimum distance between the source and the detector for which the detector detects a maximum of sound. Take the speed of sound in air=360m/s.
Regards,
Nilanjana Gupta
dimension of mass
if force, velocity, and time are taken as fundamental units then how can be find out the dimension of mass
Asked anupama at www.plustwophysics.com
potential gradient problem
in electric field, a 6.75uc charge experiences 2.5 N force , when placed at distance of 5m from the origin. then potential gradient at this point? GIVE FULL SOLUTION.
Regards,
vaibhav s. ugale
Regards,
vaibhav s. ugale
gravity and time
Has anyone considered that gravity and time are inversely related? Since it seems that time seems to come to a virtual stop beyond the event horizon of a black hole, maybe that's because whatever 'causes' time is pushed out of the way by gravity. The same might also explain the relativistic effects regarding the passage of times on objects approaching the speed of light. I mean, physics class always told us that the ground pressing back up on us was the opposite of gravity. But what if that ground just happened to be in the way, because that is the space it occupies, and it's the particle/wave/whatever that creates time that gravity actually displaces?
Regards,
Tony
Regards,
Tony
Big Bang and the conservation of Mass
Harilal asked:
“During the big bang it is supposed that the small particles expanded in a very very small interval of time and there was nothing before that. If it is so, then how can it in be good agreement with law of conservation of mass?”
Ans:
After the Big Bang, the universe expanded rapidly. The big bang theory is not a theory which is completely resolved. There are many questions to be answered.
Further, mass alone is not conserved, it is mass+energy which is conserved.
Energy can be converted into matter and vice versa. E=mc2
Dark Energy and Dark Matter are two widely discussed concepts in association with the Big Bang. These correspond to the mass (matter) and energy which we cannot account for by calculations and theory.
Further, BIGBANG is not the only possible cause of the Birth of Universe. There are many other possibilities.
Big Bang theory originated after the discovery that the universe is expanding. SO if we think in reverse direction, we can imagine that the entire universe was confined to an infinitesimally small (Compared to the present size of the universe) space. This idea started the theoritization of the Big Bang.
Please visit the following links for further reference:
http://www.aip.org/history/cosmology/ideas/bigbang.htm
http://www.aip.org/history/cosmology/ideas/journey.htm
http://en.wikipedia.org/wiki/Big_Bang
http://www.aip.org/history/cosmology/ideas/expanding.htm
(Comments and better answers are expected from visitors and experts visiting the site)
“During the big bang it is supposed that the small particles expanded in a very very small interval of time and there was nothing before that. If it is so, then how can it in be good agreement with law of conservation of mass?”
Ans:
After the Big Bang, the universe expanded rapidly. The big bang theory is not a theory which is completely resolved. There are many questions to be answered.
Further, mass alone is not conserved, it is mass+energy which is conserved.
Energy can be converted into matter and vice versa. E=mc2
Dark Energy and Dark Matter are two widely discussed concepts in association with the Big Bang. These correspond to the mass (matter) and energy which we cannot account for by calculations and theory.
Further, BIGBANG is not the only possible cause of the Birth of Universe. There are many other possibilities.
Big Bang theory originated after the discovery that the universe is expanding. SO if we think in reverse direction, we can imagine that the entire universe was confined to an infinitesimally small (Compared to the present size of the universe) space. This idea started the theoritization of the Big Bang.
Please visit the following links for further reference:
http://www.aip.org/history/cosmology/ideas/bigbang.htm
http://www.aip.org/history/cosmology/ideas/journey.htm
http://en.wikipedia.org/wiki/Big_Bang
http://www.aip.org/history/cosmology/ideas/expanding.htm
(Comments and better answers are expected from visitors and experts visiting the site)
Gauss Theorem - Electrostatics
DIVYA asked:
“WHAT IS THE MAGNITUDE OF ELECTRIC FIELD IN THE GAUSSIAN SURFACE OF A CUBE,AT ITS FACE ,AT ITS CENTRE, AT ITS CORNERS OR AT ANY OTHER POINT INSIDE THE CUBE. ALSO TELL ME THE THE WAY TO KNOW IT.”
Ans:
According to Gauss Theorem, the total electric flux through a closed surface,
The Gaussian surface is an imaginary surface. So, for calculating the electric field at a point using Gauss theorem, we have to imagine a Gaussian surface symmetric with the given charge distribution.
I have assumed that there is a point charge Q at the centre of the cube.
At its face (at a point on the face on the line radially outwards from the point charge at the centre of the cube and perpendicular to the face)
The distance is equal to half the length of side of the cube (Say L).
Therefore the electric field,
On the corner,
Calculate the distance from the centre of the cube to its corner and replace (L/2) in the above equation with that distance.
“WHAT IS THE MAGNITUDE OF ELECTRIC FIELD IN THE GAUSSIAN SURFACE OF A CUBE,AT ITS FACE ,AT ITS CENTRE, AT ITS CORNERS OR AT ANY OTHER POINT INSIDE THE CUBE. ALSO TELL ME THE THE WAY TO KNOW IT.”
Ans:
According to Gauss Theorem, the total electric flux through a closed surface,
The Gaussian surface is an imaginary surface. So, for calculating the electric field at a point using Gauss theorem, we have to imagine a Gaussian surface symmetric with the given charge distribution.
I have assumed that there is a point charge Q at the centre of the cube.
At its face (at a point on the face on the line radially outwards from the point charge at the centre of the cube and perpendicular to the face)
The distance is equal to half the length of side of the cube (Say L).
Therefore the electric field,
On the corner,
Calculate the distance from the centre of the cube to its corner and replace (L/2) in the above equation with that distance.
Time Period of a Simple Pendulum in Space
Mary Beth asked:
In a space vehicle orbiting around the earth, the apparent weight is zero as the entire gravitational pull is being utilized in providing the centripetal force required for revolving. This is called weightlessness in space.
i.e; in effect, the acceleration due to gravity is zero which make the time period of the satellite infinity. The pendulum will not oscillate at all.
However, in manned space vehicles, there is an option to simulate gravity by making the system rotate at a particular rate so as to make the inhabitants feel as if there is weight and gravity.
“if you set up a pendulum aboard an orbiting space vehicle, would the period be less than, the same as, or greater than it would be in our lab? explain.”Ans:
In a space vehicle orbiting around the earth, the apparent weight is zero as the entire gravitational pull is being utilized in providing the centripetal force required for revolving. This is called weightlessness in space.
i.e; in effect, the acceleration due to gravity is zero which make the time period of the satellite infinity. The pendulum will not oscillate at all.
__________________________________________________________
Tailpiece:However, in manned space vehicles, there is an option to simulate gravity by making the system rotate at a particular rate so as to make the inhabitants feel as if there is weight and gravity.
Pendulum on Mount Everest !
Michelle Guzman Asked:
As you know, the acceleration due to gravity decreases as we go upwards from surface of earth.
The time period of a simple pendulum is given by
Where l is the length of the pendulum, and g is the acceleration due to gravity.
From the equation, we can conclude that, the Time period of the pendulum increases (i.e. it goes slower) if the pendulum is set up on top of Mount Everest.
For Creative and Critical Thinkers
Here we have not considered the change in temperature between the laboratory conditions and the temperature on top of Mount Everest which is very low. A decrease in temperature would decrease the length of the pendulum (Unless it is made up of such a substance which does not change its length with change in temperature) and will also decrease the time period of the pendulum, making it move faster.
My first answer is correct only if the laboratory conditions are the same as on top of Mt. Everest or vice versa, except for the difference in altitude (height)
Ask Physics
If you set a pendulum atop Mt. Everest, would the period be less than, greater than or equal to the period you would get in the lab? Explain.Ans:
As you know, the acceleration due to gravity decreases as we go upwards from surface of earth.
The time period of a simple pendulum is given by
Where l is the length of the pendulum, and g is the acceleration due to gravity.From the equation, we can conclude that, the Time period of the pendulum increases (i.e. it goes slower) if the pendulum is set up on top of Mount Everest.
For Creative and Critical Thinkers
Here we have not considered the change in temperature between the laboratory conditions and the temperature on top of Mount Everest which is very low. A decrease in temperature would decrease the length of the pendulum (Unless it is made up of such a substance which does not change its length with change in temperature) and will also decrease the time period of the pendulum, making it move faster.
My first answer is correct only if the laboratory conditions are the same as on top of Mt. Everest or vice versa, except for the difference in altitude (height)
Ask Physics
A question from Kinetic energy
Atul asked:
A lorry and a car moving with the same KE are brought to rest having same retarding force .which one of them should come at rest at shorter distance.
Ans:
According to Work Kinetic Energy theorem
Both should stop travelling the same distance
(This was a quick answer without a deep thought. If the readers have a diffrent opinion, please comment)
A lorry and a car moving with the same KE are brought to rest having same retarding force .which one of them should come at rest at shorter distance.
Ans:
According to Work Kinetic Energy theorem
Both should stop travelling the same distance
(This was a quick answer without a deep thought. If the readers have a diffrent opinion, please comment)
Subscribe to:
Posts
(
Atom
)