Sunday, April 28, 2019 8:00 PM I'm actually start with what I … · 2019. 5. 2. · Screen clipping taken: 2/13/2019 3:14 PM Wednesday, February 13, 2019 3:13 PM New Section 1 Page

I'm actually start with what I believe to be the simplest question if you can recognize the type of system so that's start with the formulas you see

Free vibration - no forcing function

Forced vibration-there is a forcing function, which will be told or given to you in the form:

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Thinking about the finalSunday, April 28, 2019 8:00 PM

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When you are given a problem, transform it into a system with and (HOWEVER THIS ONLY APPLIES WHEN U R AT THE CENTER OF MASS)

1)


To get around that problem we use2)

Now draw the forces like a regular FBD and draw the conversion to the system with one shown above

3)

Now analyze the forces to determine the linear acceleration, with regular analysis we know before we even started this course

4)

Now analyze the moments (through forces),be careful about distances to find the angular acceleration

5)

YOU MIGHT HAVE TO USE CONCEPTS FROM THE PREVIOUS 2 UNITS6)

Now that's look at the transformation of a system to a system with both a linear and angular acceleration

Sunday, April 28, 2019 10:18 PM



Now some problemsSunday, April 28, 2019 10:39 PM




This is the same equation we applied before except the new thing due to rotation is there are 2 forms of rotational kinetic energy now


And one more thing changes with rotation the way we find the value of work done by non-conservative, it is not force over distance, it is now moment over angle

Now we can apply the idea of energy conservationSunday, April 28, 2019 10:51 PM



Sunday, April 28, 2019 11:00 PM



MomentumSunday, April 28, 2019 11:14 PM


What the hell am I supposed to do?Monday, February 11, 2019 4:41 PM

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Here is the problem, tell me the method u are going to use:

A mass is being swung around a person's head as shown below. What is the total acceleration if the tangential velocity increases from m/s to 2 m/s in 0.5 sec?

1)

Think: Do_______________ and then _____________a.

In the diagram shown below, if the spring has an unstretched length of 200 cm, what is normal force on the bar just before it passes point B? (Trick kinda question here)

2)

What is the velocity of the block if the tension in the cable of 500 N acts on the block for 2 seconds and the block starts from rest?

3)

Basic motion problemMonday, February 11, 2019 4:52 PM


How far up the slides does the block go if it is released from the spring but glides over a patch of friction?

4)

5)


The method of forcesMonday, February 11, 2019 6:20 PM




Wednesday, February 13, 2019 2:24 PM




In case of failure, a surface is put around the track with a coefficient of friction of 0.10, if there is failure at the point described above, how far would the car travel in tangential direction? (Ignore sliding due to unbalanced forces, pretend it goes in the perfectly tangential direction after it loses contact with the track?



Some idiot decided to build a wall 10 meters in the tangential direction at that point, is a collision going to occur? If so, if the collision lasts 3 seconds, and the maximum force during impact in that style car a person can handle without death is 1000 lb, will the person survive?








Relative MotionWednesday, February 13, 2019 3:16 PM




At that point, the projectile collides with a 2 kg mass falling at 3 m/s. After the collision, the object stick together, what is the velocity of the resulting combined system in component form?. What is the amount of energy lost in the collision and where does it go?

Instead of another object, there is a spring at the same angle to allow perfect



Instead of another object, there is a spring at the same angle to allow perfect compression (not an angle where u have to worry about a part of velocity), what is the displacement of the spring (in the I hat direction) if the uncompressed distance is 2 m? (Will put in diagram so it is not confusing)


________________________ when _______________________i.________________________ when _______________________ii.________________________ when _______________________iii.

The 3 coordinate systems we use area.

Newton's second law says______________________b.Normal acceleration applies if the object is moving along a ______________c.Kg is to Newton as _______________ is to________________(English system)d.The standard units for velocity are ______________(Metric) and _____________(English)e.The standard units for accelration are ______________(Metric) and _____________(English)f.

General1.

The last couple questionsWednesday, February 13, 2019 5:09 PM


Sunday, February 17, 2019 2:40 PM



To start ICV is usually used when it asks for the velocityCANNOT BE USED FOR ACCELERATION

In these problems usually it is just rigid bodies and u are given the velocity of oneAnd u are asked to find the velocity (Angular or regular) of one of the joints

Draw velocity arrows1)Draw radius vectors at 90 degrees2)Label where they meet3)Use trig to find lengths4)Use the fact to solve for velocities or angular velocities5)

Steps

GeneralTuesday, March 26, 2019 11:39 AM

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Now on to the translating axis

We know the basic equations for relative motion:

Only thing about the acceleration relative motion equation, there are 2 forms of acceleration

That's take a trip down memory lane, physics 1, rotational variables

So if the thing is spinning in a circle, there must be normal acceleration

And if it is speeding up rotational, meaning omega is increasing, so if the problem says constant angular speed for the part of interest there is no tangential acceleration

Now if u notice these equations involve radius, velocities and omegas as unknown variables. Use the relative motion and ICV equations to find those unknowns

Now Translating AxisTuesday, March 26, 2019 11:53 AM

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Now the equations given to u are:

Now the hardest part: Translating and rotating axisTuesday, March 26, 2019 2:33 PM

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Decide if your frame is translating or rotating, 99% chance there won't be both1)Write down the BASIC EQUATION FOR RELATIVE ACCELRATION2)Expand all terms to include normal and tangential components3)

CONSTANT ANGULAR VELOCITY FOR THAT PART, NO ALPHAa.If it is not moving in a circle (no omega), no normal accelerationb.Moving ALONG A STRAIGHT LINE AT A CONSTANT VELOCITY, NO ACCEL.c.

If u can, eliminate terms you know will be zero, like…4)

Expand normal and tangential components, be careful of subscripts5)Decide on direction for omegas and alphas, plug in what u know, do the cross product

6)

Now look at what you have, decide what you are solving for, and check how many unknowns, if the equation has I's and j's, there can be 2 unknowns and u can solve

7)

Think of as a system of equationsa.Now set up 2 equations, 1 for the I's and j's8)

Remember the relative velocity and acceleration point from the point of origin on the rotation axis to the point of interest, points in same direction as radius except where the velocity vector(relative) can be expressed as the magnitude of velocity times the direction, which if you know the radius, you know the angle and therefore you know the direction vector

1)

Draw the frame which will help for finding all the variables2)Remember if they give you the relative velocity or acceleration, that is the magnitude, and you still need to have a direction to break into vector form to apply the equation

3)

Notes on rotational, probably the hardest

General rules for accelerationWednesday, March 27, 2019 6:24 PM

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Wednesday, March 27, 2019 6:21 PM

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Now if u notice these equations involve radius, velocities and omegas as unknown variables. Use the relative motion and ICV equations to find those unknowns


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v


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Sunday, April 28, 2019 8:00 PM I'm actually start with what I … · 2019. 5. 2. · Screen clipping taken: 2/13/2019 3:14 PM Wednesday, February 13, 2019 3:13 PM New Section 1 Page