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)6) Decide on direction for omegas and alphas, plug in what u know, do the cross

productNow 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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v

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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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Problem 1Tuesday, March 26, 2019 2:53 PM

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