Pendulum RotationA simple pendulumCan an integral of a function that is not well behaved be finite?Lagrangian...
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It took me a lot of time to make this, pls like. (YouTube Comments #1)
Pendulum Rotation
A simple pendulumCan an integral of a function that is not well behaved be finite?Lagrangian of bead on a rotating hoopEuler-Lagrange - circle coneInclined plane - euler-lagrangeAngular Velocity calculationQuestion on inclined plane with velocity of projection $u$ both up and down plane.Finding the Velocity of a Particle after an ImpactWhat is the equation of the trajectory from the second bounce?Physics answers obtained through two different mathematical approaches contradict.
$begingroup$
A simple pendulum has a bob with a mass of .50 kg. The cord has a length of 1.5 m, and the bob is displaced $20^circ$.
I am trying to use this expression to find the maximum velocity of the bob.
$$omega^2_f=2 alphatriangletheta$$
I get the following expression:
$$frac{v^2}{L^2}=2Lfrac{mgsintheta}{I}triangletheta$$
Is this expression correct to solve the question?
mathematical-physics
$endgroup$
add a comment |
$begingroup$
A simple pendulum has a bob with a mass of .50 kg. The cord has a length of 1.5 m, and the bob is displaced $20^circ$.
I am trying to use this expression to find the maximum velocity of the bob.
$$omega^2_f=2 alphatriangletheta$$
I get the following expression:
$$frac{v^2}{L^2}=2Lfrac{mgsintheta}{I}triangletheta$$
Is this expression correct to solve the question?
mathematical-physics
$endgroup$
add a comment |
$begingroup$
A simple pendulum has a bob with a mass of .50 kg. The cord has a length of 1.5 m, and the bob is displaced $20^circ$.
I am trying to use this expression to find the maximum velocity of the bob.
$$omega^2_f=2 alphatriangletheta$$
I get the following expression:
$$frac{v^2}{L^2}=2Lfrac{mgsintheta}{I}triangletheta$$
Is this expression correct to solve the question?
mathematical-physics
$endgroup$
A simple pendulum has a bob with a mass of .50 kg. The cord has a length of 1.5 m, and the bob is displaced $20^circ$.
I am trying to use this expression to find the maximum velocity of the bob.
$$omega^2_f=2 alphatriangletheta$$
I get the following expression:
$$frac{v^2}{L^2}=2Lfrac{mgsintheta}{I}triangletheta$$
Is this expression correct to solve the question?
mathematical-physics
mathematical-physics
edited 1 hour ago
EnlightenedFunky
asked 1 hour ago
EnlightenedFunkyEnlightenedFunky
81211022
81211022
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
First of all, you should explain what your parameters are. But you seem to over complicate the problem. Write conservation of energy. At the bottom of the trajectory, we choose the potential energy to be $0$. Then you have only kinetic energy $frac 12 mv^2$. At the top of the trajectory, the bob is at rest, so kinetic energy is zero, and you have only potential energy. The height of the bob is $L(1-costheta)$, so $$mgL(1-costheta)=frac 12 mv^2$$
Notice that the velocity is independent of mass
$endgroup$
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
|
show 1 more comment
$begingroup$
The equation only holds when angular acceleration $alpha$ is a constant. However in this case $alpha=frac{gsintheta}{l}$, which depends on $theta$
New contributor
$endgroup$
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
First of all, you should explain what your parameters are. But you seem to over complicate the problem. Write conservation of energy. At the bottom of the trajectory, we choose the potential energy to be $0$. Then you have only kinetic energy $frac 12 mv^2$. At the top of the trajectory, the bob is at rest, so kinetic energy is zero, and you have only potential energy. The height of the bob is $L(1-costheta)$, so $$mgL(1-costheta)=frac 12 mv^2$$
Notice that the velocity is independent of mass
$endgroup$
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
|
show 1 more comment
$begingroup$
First of all, you should explain what your parameters are. But you seem to over complicate the problem. Write conservation of energy. At the bottom of the trajectory, we choose the potential energy to be $0$. Then you have only kinetic energy $frac 12 mv^2$. At the top of the trajectory, the bob is at rest, so kinetic energy is zero, and you have only potential energy. The height of the bob is $L(1-costheta)$, so $$mgL(1-costheta)=frac 12 mv^2$$
Notice that the velocity is independent of mass
$endgroup$
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
|
show 1 more comment
$begingroup$
First of all, you should explain what your parameters are. But you seem to over complicate the problem. Write conservation of energy. At the bottom of the trajectory, we choose the potential energy to be $0$. Then you have only kinetic energy $frac 12 mv^2$. At the top of the trajectory, the bob is at rest, so kinetic energy is zero, and you have only potential energy. The height of the bob is $L(1-costheta)$, so $$mgL(1-costheta)=frac 12 mv^2$$
Notice that the velocity is independent of mass
$endgroup$
First of all, you should explain what your parameters are. But you seem to over complicate the problem. Write conservation of energy. At the bottom of the trajectory, we choose the potential energy to be $0$. Then you have only kinetic energy $frac 12 mv^2$. At the top of the trajectory, the bob is at rest, so kinetic energy is zero, and you have only potential energy. The height of the bob is $L(1-costheta)$, so $$mgL(1-costheta)=frac 12 mv^2$$
Notice that the velocity is independent of mass
answered 1 hour ago
AndreiAndrei
12.5k21128
12.5k21128
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
|
show 1 more comment
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
But, I would like to solve this particular manner the professor solved it that way already.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
Secondly, everything was given to you.in the detail.
$endgroup$
– EnlightenedFunky
1 hour ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
You did not explain what the $alpha$ or $I$ or $omega_f$ are. I guessed that you they represent angular acceleration, moment of inertia, and angular velocity. However, the formula that you wrote cannot be used in this case. That formula is valid for constant $alpha$, which is not the case here. The torque depends on the angle between gravity and the cord.
$endgroup$
– Andrei
55 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
Isn't the force is $mgsintheta$
$endgroup$
– EnlightenedFunky
52 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
$begingroup$
No, the force is $mg$ always pointing downwards. The torque is $mgLsintheta$
$endgroup$
– Andrei
48 mins ago
|
show 1 more comment
$begingroup$
The equation only holds when angular acceleration $alpha$ is a constant. However in this case $alpha=frac{gsintheta}{l}$, which depends on $theta$
New contributor
$endgroup$
add a comment |
$begingroup$
The equation only holds when angular acceleration $alpha$ is a constant. However in this case $alpha=frac{gsintheta}{l}$, which depends on $theta$
New contributor
$endgroup$
add a comment |
$begingroup$
The equation only holds when angular acceleration $alpha$ is a constant. However in this case $alpha=frac{gsintheta}{l}$, which depends on $theta$
New contributor
$endgroup$
The equation only holds when angular acceleration $alpha$ is a constant. However in this case $alpha=frac{gsintheta}{l}$, which depends on $theta$
New contributor
New contributor
answered 52 mins ago
Yuzheng LinYuzheng Lin
411
411
New contributor
New contributor
add a comment |
add a comment |
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