7. Degrees of Freedom, Free Body Diagrams, & Fictitious Forces

MIT 2.003SC Engineering Dynamics, Fall 2011
Instructor: J. Kim Vandiver

License: Creative Commons BY-NC-SA

[georgesadler]

DR. Vandiver, thank you for a awesome explanation of the Degrees of Freedom, Free Body Diagrams and Fictitious Forces in Engineering Dynamics. MIT really brings out the best in all technical subjects.

[jyotirmoybarman]

Find the number of degrees of freedom for a rigid body which can move freely in three dimensional space has one point fixed but can move in space about this point.

[muhammadhalawa]

In the elevator problem, shouldn't the scale read at maximum the weight of the person ? The scale is only a spring in its simplest model, and the reading is taken from the spring deflection, the forces contributing to spring deflection are only the forces that compress it (i.e if I have a spring with 1000N from this side => spring <= 20N from this side, the I will have 20 N compressing the spring and 980N accelerating in the 1000N direction).
If we did the experiment I believe the scale will read more than the person's weight at START, but that's due to shock effects, in other words while in the transient state (the period until the force reaches the whole spring and move it without relative motion between one coil and another)

[pravinkumarkale]

I have little doubts: I understand all other constraints but I did not understood how they consider constraints in y direction as wheel can have up and down vertical motion so how we can consider there is no any movement in the direction of y.

[josuemanuelparejacontreras]

I have one doubt, why the moment arm at 1:02:20 is not the result vector of r and z ? why just z?. Thank you very much for these lectures!!!

[NYKYADU]

where can I find the home work problems he keeps on mentioning?

[umdbest]

awesome..thanks a lot for making studyng interactive

[tag_of_frank]

How can it be a fictitious force if it is causing a bending moment on the beam?