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1 a) When using T = 1/2Iw^2 + 1/2mvG^2 for kinetic energy of a planar rigid body

ID: 1396010 • Letter: 1

Question

1 a) When using T = 1/2Iw^2 + 1/2mvG^2 for kinetic energy of a planar rigid body, what point must the mass moment of inertia, I, be found about? a. A fixed point of rotation The center of mass Any arbitrary point A or B 1 b) A child at point A walks at constant rate toward the center of a merry-go-round which is rotating at constant angular velocity w counter clockwise. What is the direction of the child's Coriolis acceleration? a. +X b. -x C. +Y d. -Y In mechanical work energy, when will T1+V1=T2+V2? When there are no non-conservative forces or moments present doing work Always When there is no heat or noise dissipating mechanical energy When the work of internal forces and moments cancel out

Explanation / Answer

1

a)

Moment of inertia must be found about the fixed axis of rotation or center of mass <---------answer

It depends upon the way the body is rolling or rotating. Accordingly the answer will be either of them

b)

The coriolis acceleration direction is given by the vector product of angular velocity and velocity of the person.

Now, angular velocty is in direction of +z axis <--- counter clockwise rotation

velocity of man in -x axis

So, direction of coriolis acceleration = cross product of (+z) and (-x) = -Y <--------answer

c)

The equation only holds when there are no non-conservative forces or moments are present doing work