Very nice teaching, please upload lectures of Solid Mechanics as well by this teacher itself. It's my humble request to IIT Madras. A big fan of his teaching.
Dear learner, We are happy to announce that a new full-length course on Strength of Materials offered by Prof K Ramesh with extensive animations and experiments is now available at the following link: ruclips.net/p/PLJoALJA_KMOARYNi50T6b488kPUBbOIsX Happy learning, EM TA
At 18:48, Would it translate if the resultant is not along the centre of mass? In other words, in this lecture I came to know that concurrent coplanar system(say 3 force-system) cant produce moment or rotation, but, what if the resultant of that very force system doesn't pass through the centre of mass?
It is a very good question based on keen observation. In fact, the body indeed would rotate if the net moment about the centre of mass is non-zero. Concurrent force systems do not produce a moment about the point of intersection of the lines of action of the forces. Therefore, a particle present at that point would have only translation. A particle, by definition, is a point mass with zero dimensions (negligible size). A system of forces acting on a single particle would have to be invariably concurrent. Therefore, there can be no moment acting on a single particle. However, while considering a system of particles, the force systems need not be concurrent and therefore, moments can exist. However, if moments are absent on a system of particles, it can be idealized as a particle (the centre of mass). While learning the dynamics portion of this course, you will later see that rotating objects cannot be idealized as particles irrespective of the size.
At 11:40 it is said that if weight is involved, there must be at least three forces. Why is that so? Suppose the case of holding a ball in air by a vertical string. There are only two forces: the weight of the ball, and tension in the string.
What stops that ball from swinging? What restricts the motion of the ball in the horizontal plane? Well clearly there must be forces balancing out each other thus keeping the ball in equilibrium. And there must be atleast two of them.
how are we able to change the state of an object without net external force on it? There is moment in absence of net force, means the body rotates without any net force? How is this possible?
The net force zero is referring to the net translational force being zero. The moment as you know is a measure of the rotational tendency, that isn't zero. So due to this object will tend to rotate rather than move in any direction. I think this is the explanation. Please correct me if I am wrong.
@nilesh rathod and @gautham krishnan this thing got me thinking now. In absence of force how could the object rotate. The moment is the measure of rotational tendency yes but it requires an external force to start the rotation in first place. I know this comment was posted months ago. Please revert if you have found the answer to this confusion.
@nilesh rathod @Gautham Krishnan @sufiyan sayeed Unlike force where one is concerned only with the line of action of the force, moment depends on the line of action of the force and point about which moment is calculated. Moment M = r x F Note that absence of net external force can be a consequence of either cases mentioned below: 1. No force is applied on the body. Here, net external force is zero and net external moment is zero since F = 0 in r x F 2. Forces (say F1 & F2) are applied on a body but their vector sum (resultant) comes out to be zero. Here, net external force is zero since F1 + F2 = 0 (vector sum) but moment is not always zero since it is r1 x F1 + r2 x F2. It will depend on which point is selected. r1 and r2 need not always be equal and therefore, net external moment can exist with a net external force. Hope its clear now.
Very nice teaching, please upload lectures of Solid Mechanics as well by this teacher itself. It's my humble request to IIT Madras. A big fan of his teaching.
u r studying in?
A trick: you can watch movies on flixzone. Been using them for watching lots of of movies these days.
Dear learner,
We are happy to announce that a new full-length course on Strength of Materials offered by Prof K Ramesh with extensive animations and experiments is now available at the following link:
ruclips.net/p/PLJoALJA_KMOARYNi50T6b488kPUBbOIsX
Happy learning,
EM TA
best lectures on engineering mechanics , the way sir teach is fabulous
At 18:48, Would it translate if the resultant is not along the centre of mass? In other words, in this lecture I came to know that concurrent coplanar system(say 3 force-system) cant produce moment or rotation, but, what if the resultant of that very force system doesn't pass through the centre of mass?
It is a very good question based on keen observation.
In fact, the body indeed would rotate if the net moment about the centre of mass is non-zero.
Concurrent force systems do not produce a moment about the point of intersection of the lines of action of the forces. Therefore, a particle present at that point would have only translation.
A particle, by definition, is a point mass with zero dimensions (negligible size).
A system of forces acting on a single particle would have to be invariably concurrent. Therefore, there can be no moment acting on a single particle.
However, while considering a system of particles, the force systems need not be concurrent and therefore, moments can exist. However, if moments are absent on a system of particles, it can be idealized as a particle (the centre of mass).
While learning the dynamics portion of this course, you will later see that rotating objects cannot be idealized as particles irrespective of the size.
Thank you Team DTH, teachers,mediators❤
9:02 which book is sir talking about?
Nice teaching sir I got my all concepts crystal clear
At 11:40 it is said that if weight is involved, there must be at least three forces. Why is that so? Suppose the case of holding a ball in air by a vertical string. There are only two forces: the weight of the ball, and tension in the string.
I think he is talking about forces in horizontal directions....
@@Cool_as_Sun what other force is there in the horizontal direction?
@@SohamChakraborty42069 in which case?
What stops that ball from swinging?
What restricts the motion of the ball in the horizontal plane? Well clearly there must be forces balancing out each other thus keeping the ball in equilibrium. And there must be atleast two of them.
Thank you for your very good lecture, Sir.
r u japanese???
12:10 mein weight mein agar koi object ground pe rakha gaya hai to weight normal se balance ho jaayega na to use consider karke bhi koi matlab nhi hai
40:09. What a funny way to explain the restraints!!
thank you sir!! very good explanation
Thank you sir 🙏.
very helpful all real life example to understand clearly, thank you sir
Kindly upload lecture ppt.
Can anyone help me solve the nptel quiz 🤕 questions aren't easy
Translation in hindi is not properly audible and not convincing. Plese remove Hindi Translation. Sirs English is very simple and understandable
🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼
Thankyou...
I am a graduate from University of Technology Sydney
it's helpful.
🔥
how are we able to change the state of an object without net external force on it? There is moment in absence of net force, means the body rotates without any net force? How is this possible?
The net force zero is referring to the net translational force being zero. The moment as you know is a measure of the rotational tendency, that isn't zero. So due to this object will tend to rotate rather than move in any direction. I think this is the explanation. Please correct me if I am wrong.
@nilesh rathod and @gautham krishnan this thing got me thinking now. In absence of force how could the object rotate. The moment is the measure of rotational tendency yes but it requires an external force to start the rotation in first place. I know this comment was posted months ago. Please revert if you have found the answer to this confusion.
@nilesh rathod @Gautham Krishnan @sufiyan sayeed
Unlike force where one is concerned only with the line of action of the force, moment depends on the line of action of the force and point about which moment is calculated.
Moment M = r x F
Note that absence of net external force can be a consequence of either cases mentioned below:
1. No force is applied on the body. Here, net external force is zero and net external moment is zero since F = 0 in r x F
2. Forces (say F1 & F2) are applied on a body but their vector sum (resultant) comes out to be zero. Here, net external force is zero since F1 + F2 = 0 (vector sum) but moment is not always zero since it is r1 x F1 + r2 x F2. It will depend on which point is selected. r1 and r2 need not always be equal and therefore, net external moment can exist with a net external force.
Hope its clear now.
🥰😍😍😍