Engineering Statics

William Haynes on Equilibrium of a rigid body: truss 2 months ago

Saved a checkpoint:

Turned off debug mode (oops), and edited the ggb applet to turn off gridlines and scale.

Jay McCormack on Vector addition by summing scalar components - easy 3 months, 1 week ago

Gave some feedback: Ready to use

Cyril Crua commented on V-M 1: Concentrated forces 7 months ago

Many thanks for these excellent resources. I think there may be an inconsistency in sign convention in this and other beam exercises, as the shear and moment signs don't seem to match those in http://engineeringstatics.org/VM_sign_convention.html 

William Haynes commented on 16. Equivalent Systems, Resultants 7 months, 2 weeks ago

Added question: equivalent force couple system on bracket

William Haynes on Equivalent Force-couple system: Bracket 7 months, 2 weeks ago

Gave some feedback: Ready to use

William Haynes on Equilibrium of a rigid body: beam and pulley 8 months, 1 week ago

Saved a checkpoint:

Properly italicized variables, reformatted advise.

William Haynes on Equilibrium of a rigid body: truss 8 months, 1 week ago

Saved a checkpoint:

When b=2.8, h=4, B=2, C=5, F=4, E=3, then Ay = 0, but  Numbas calculates it as Ay = -1.7763568394002505*10^(-15) and marks 0 wrong, because it calculates percent error to be 100 %

abs(0 - 0.00000000000002)/(0.00000000000002) = 1.

Added precround(Ay,6) in Marking settings to avoid this.  I don't know how to fix the root cause.

William Haynes on 13. Equilibrium of Rigid Bodies 8 months, 1 week ago

Saved a checkpoint:

Student reports that when A_y = 0, answer is not marked correct.

William Haynes on Equilibrium of a particle: four forces 8 months, 1 week ago

Gave some feedback: Has some problems

William Haynes on Equilibrium of a particle: four forces 8 months, 2 weeks ago

Saved a checkpoint:

Problem is throwing "undefined is not an object (evaluating 'original_result.states.mark')" when answer is submitted.  Resubmitting it works.  

William Haynes on Equilibrium of a particle: four forces 8 months, 3 weeks ago

Saved a checkpoint:

No bug, student misinterpreted the question leading to his problem

William Haynes on Equilibrium of a particle: four forces 8 months, 3 weeks ago

Saved a checkpoint:

Bug in marking algorithm reported

William Haynes on Friction: Range of values 2 9 months ago

Gave some feedback: Ready to use

William Haynes on Friction: Range of values 1 9 months ago

Gave some feedback: Ready to use

William Haynes on Friction: Determine direction of $F_f$ 9 months ago

Gave some feedback: Ready to use