https://www.physicsforums.com/thread...xtbook.958929/

Thanks! ]]>

There is a pulley. On the left side hangs object of Mass M and height L. On the other side a bead of mass m slides down the rope. After release from rest, bead passes the Object in time T.

What is the friction force (lets call it "P") of the bead?

What is the acceleration of bead ("a") and the object ("A") in reference to Earth?

So Newtons 2nd law for object M: MA= Mg - P

for bead m: ma= mg - P

So P= mg - ma and I am supposed to find a using L and T? ]]>

R=3m

Vo=1.5 m\s

epsilon=0.5

rad\s^2

omega=2 rad\s

I need to find the Absolute Velocity when the person walks to the end of the circle (radius) ]]>

I'm not sure where to start with this question if someone could help me out that would be great. Thanks! ]]>

many joules are supplied to the battery?

Can someone explain what is ampere-hours also, plz. ]]>

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One is angular radius of central bright is given 1.22 lamda/D

Other is diameter of central bright is kanda/D.

Which one is correct. ? ]]>

Any help to solve this problem ? i will be so thankful .

Best regards

A rigid uniform beam (0.5m in length) of weight 200N is hinged to a wall and held horizontally by a string 40 degrees to the horizontal. a) Calculate the tension in the string. b) The horizontal contact force of the wall on the hinge.

I’m assuming I have to use moments?

I think the weight would provide a clockwise moment

m = Fs

= 200N x 0.25 (because I think the weight will act in the centre of the beam?)

This will equal the anti-clockwise moment provides by the tension in the string.

For this would I work out the vertical component? I’m lost on what I have to do to be honest, any help would be appreciated. ]]>

Any help to solve this problem ? i will be so thankful .

Note : This problem is not homework .

My final project (undergrad thesis) involves modeling the pulling force of a winch.

As the problem involves a rope under tension and a block being pulled on a surface (friction considered), I can model the problem as a damped spring mass system (due to the internal friction of the rope). The force on the string is expected to peak and then decrease to its nominal value.

As a guide, I used the example of Machine Design - An Integrated Approach, 3rd edition - Robert L Norton.

[B] MODELING METHOD [/ B]

1. Define the differential equation

Attachment 2319

Figure 1 shows the Dynamic System, the Lumped Model and the Free Body Diagram (From the book problem)

(My differential equation is analogous to the Norton example. The difference is that the load to be pulled is horizontal)

Attachment 2320

Figure 2 shows the model on my problem.

2. Define Boundary Conditions

The initial conditions reflect the fact that the system is initially stopped. Speeds, displacements and accelerations are all equal to zero.

Attachment 2321

Figure 3 shows the boundary conditions of the Norton problem, which are analogous to mine the resulting equation, with physical constants already substituted. Note that g does not fit into my equation. In my problem, g will be replaced by the ratio of [MATH] (F_friction + F_resistance) / m [/ MATH]

3. Solving the equation and plotting the graphs.

Attachment 2322

Figure 4 shows the results of the book, which are congruent with the expected response to the actual physical situation.

[B] MY RESULTS [/ B]

Attachment 2323

Figure 5 shows the equation with my values already plugged in. (Equation-A)

Solving Equation - A on https://www.symbolab.com/solver/seco...ion-calculator,

Attachment 2324

We have the solution - Figure 6

Plotting its second derivative in Wolphram, we obtain the graph of Figure 7. So far, all okay.

Attachment 2325

However, I do not know how to plot the force graph.

I tried to multiply the mass of the block by the acceleration equation (second derivative of the solution of equation A) and plot the result and I got what we see in Figure 8

Attachment 2326

It does not match the reality of the problem.

Can you tell me where I'm going wrong? The force should tend to the nominal force (F_winch or F_friction _ F_resistance), as in the Norton problem, not zero.

Please help guys!