Tagged Questions

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Question about torque and center of mass [duplicate]

If a yo-yo's string is not attached to anything and the yo-yo is dropped, it is obvious it will fall at $g$. In this scenario, Tension of string = 0. If a yo-yo's string is attached to a cieling and ...
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What is the linear and rotational motions generated by a force not on the CG?

Given a force that is applied to a free body, not directly towards, or away from the centre of gravity, how would you calculate the amount of linear and rotational velocities generated, as the farther ...
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Rotational behavior of objects in zero-g with forces [closed]

I would like to know how this object would rotate in free space out of curiosity. Below is a diagram of the object. It is of uniform density and has a center of mass in the center of the object, ...
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Falling off a chair, how best to save yourself

If I consider a man sitting on an office chair that reclines backwards iff you lean backwards. What could be done to prevent hin from falling? a) raising his legs till they are parallel to ground. ...
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A question about biceps and rotational equilibrium

I know that as the angle of the elbow increases, the force of the bicep increases. i.e. when angle is 180, arm is fully extended and there is 0 force from bicep. When the elbow angle is smaller there ...
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Why is it easier to turn a heavy hanging object?

Assume if we had a 2 tonne weight placed on ground attached with a rope that we can use to turn the object around. It will immensely hard to turn that object around by pulling the rope. However, if ...
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Taking pivot about an accelerating point

Given this question: A small ball of mass $m$ and radius $r$ rolls without slipping on the inside surface of a fixed hemispherical bowl of radius $R>r$. What is the frequency of small ...
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Toppling of a cylinder on a block

A uniform cylinder rests on a cart.The height and diameter is given.coefficient of static friction is given.How can i find the minimum acceleration of block such that the block topples? Morever what ...
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How do bicycle spokes work?

As you know, it is quite obvious that Bicycle spokes attach the hub in the centre to the rim. What else do they do? If you compare the wheels today with the ones from ancient times, there are more ...
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Ask an equation to solve the next location of an object?

It is a long time that I have not learnt physics. But now I really need an equation to solve a problem. I appreciate physicists give me a little hint. Here is a object on the desk without friction. ...
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Direction of friction in case of a rolling sphere

Suppose a ball rolls on a ground .obviously it is friction that helps to develop the required torque.Hence I find the direction of friction by pointing out the direction of rolling of the ball. But is ...
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How to end up with Newtons in the calculation of the lift force

In another StackExchange Physics question, @Rego had found the following equation to calculate the lift force generated by a simple rectangular blade. $$F = \omega^2 L^2 l\rho\sin^2\phi$$ in ...
505 views

Forces acting on a point mass in a spinning rigid body

I have learned that all spinning objects will continue spinning even if no force is acting on it, and the tendency to do so is called moment of inertia. But I wonder about the fact that a single point ...
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Fading transition and rotation of and object in 2D

I'm looking for sources about I guess dynamics subject. The model I'd like to solve is reduced to a question of: How does a force applied on a certain point of an object results in both fading ...
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Kinetic Energy And Rotational Motion

The problem is, "A metal can containing condensed mushroom soup has mass 220 g, height 11.0 cm and diameter 6.38 cm. It is placed at rest on its side at the top of a 3.00-m-long incline that is at ...
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Which direction will the yoyo move?

This question has been around the net for a while, and I haven't seen a good explanation for it: A yo-yo is initially at rest on a horizontal surface. A string is pulled in the direction shown in ...
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Tensions And Pulleys With Masses

The problem I am working on is: "A block of mass m1 = 1.80 kg and a block of mass m2 = 6.30 kg are connected by a massless string over a pulley in the shape of a solid disk having radius R = 0.250 m ...
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Force applied off center on an object

Assume there is a rigid body in deep space with mass $m$ and moment of inertia $I$. A force that varies with time, $F(t)$, is applied to the body off-center at a distance $r$ from its center of mass. ...
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How to interpret this vertical circular motion problem?

A bucket of water is tied to a rope and swung in a vertical circle. The distance from the bucket centre to the axis of rotation is $2.08m$. Calculate the angular velocity (in $rad s^{-1}$) of ...
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What techniques can be used to analyze a rod rotating about the edge of a table?

A uniform rod of length $4x$ is rotating about the edge $O$ of the table. (The rod does not fall off the table.) The centre of mass $G$ of the rod is distance $x$ away from $O$. The rod is making ...
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Normal force in a compound pendulum (physical pundulum) system?

Consider a compound pendulum pivoted about a fixed horizontal axis, illustrated by the force diagram on the right: # Okay, I can't figure out where the normal force on the pendlum should point ...
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What sustains a rigid body's rotation at its constant angular(rotational) speed?

Continuing from the following scenario from my previous question Centripetal force of a rotating rigid body? : Consider someone pushing a roundabout in a playground. Initially the roundabout is ...
2k views

Centripetal force of a rotating rigid body?

Consider someone pushing a roundabout in a playground. Initially the roundabout is stationary, but when it is pushed, it rotates with increasing rotational speed. The force of the push is ...
1k views

Calculation for force generated by a rotating rectangular blade

When trying to calculate the lift force generated by a simple rectangular blade, I've found the following equation: $$F = \omega^2 L^2 l\rho\sin^2\phi$$ in which $\omega$ is the angular velocity, $L$ ...