ja72

3,551 reputation

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Started programming on a ZX spectrum in the 80's and have moved through Assembly, Turbo Pascal, C++, C#, Fortran. My main area of focus is engineering and scientific computing like numerical methods and 3D graphics.

	3,551 reputation	bio	website		visits	member for	2 years, 6 months
522 badges		location	United States		seen	1 hour ago

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8h	answered	How is it that angular velocities are vectors, while rotations aren't?
8h	comment	How is it that angular velocities are vectors, while rotations aren't? @MarkEichenlaub, the physics behind angular velocities is that their direction describe the direction of the screw axis of natural motion for a rigid body, and their magnitude the rate of change of angle about the screw axis. The location and pitch of the screw axis are computed if the linear velocity is given at any point on the rigid body. It is not just math.
9h	comment	Short-duration forces Who said that? References?
12h	revised	What is the distance traveled edited body
14h	answered	Deriving $T = F\ r = I\alpha$ for a rigid body
1d	comment	Where does the extra equation come from to determine the forces from an object on a table? This answer will give good results. Car race teams use it all the time to estimate the weight each tire supports.
1d	comment	Finding the force of an object? What is an "evenly dismounted load"? You mean evenly distributed load?
1d	comment	Finding the force of an object? Sum of forces is mass times acceleration ... That is your starting point.
1d	answered	What is the distance traveled
1d	comment	What is the distance traveled @user1665835, as soon the as coin starts to tilt it will contact the pen on one point only. And I disagree with Adam, you can deduce some things from this setup.
1d	comment	What is the distance traveled Where exactly is the pen hitting the coin in relation to the center of the coin?
2d	revised	What is the distance traveled added 27 characters in body
2d	comment	What is the distance traveled A sketch would be greatly appreciated. I have trouble understanding the situation.
May 19	comment	Spring damper model does not work very well @Greg, no this formula is for constant acceleration. The OP is talking about a numerical solution where the acceleration changes with position and velocity.
May 19	comment	Why are some jenga pieces easier to remove than others? @BrandonEnright, I agree as you can see from my comment on the OP.
May 19	answered	Why are some jenga pieces easier to remove than others?
May 19	comment	Why are some jenga pieces easier to remove than others? Note that small size changes affect the load distribution among neighboring blocks.
May 19	comment	Why are some jenga pieces easier to remove than others? For each block, sum of forces equals zero and sum of moments equals zero. That's how you calculate the internal forces.
May 19	comment	How do determine the equation of motion of slinky? @user24642 Lookup online for multi-mass spring modeling, and maybe it will steer you towards a way of dealing with this.
May 19	comment	How do determine the equation of motion of slinky? A slinky is a one long beam, with end points contacting the ground and coils clashing. Not en easy problem to deal with in general.