Mark Johnson

[Mark Johnson @MrQuackTactics]

Everyday example of damped vibration: My rubber phone cover every time I get a text. #engmech

[Mark Johnson @MrQuackTactics]

@wesley_schulte Yeah, it is. If an inexperienced player doesn't press hard enough on the strings, the vibration is damped. #engmech

[Mark Johnson @MrQuackTactics]

@NGFroynd The ball is vibrating at the moment it hits the ground, but bouncing itself isn't. It does folllow a sin curve though. #engmech

[Mark Johnson @MrQuackTactics]

@Keeler52 @steffl1810 Auto manufacturers must determine the vibrations in order to design the suspension system. #engmech

[Mark Johnson @MrQuackTactics]

@steffl1810 @Keeler52 I believe that they designed the bridges natural frequecy wrong. It resonated at wind speeds of 40 mph. #engmech

[Mark Johnson @MrQuackTactics]

http://t.co/dvjkuPkUze Here's a video that demonstrates the importance of reducing vibration for surface finish. See 2:18. #engmech

[Mark Johnson @MrQuackTactics]

@M_Menkabo @YouTube That's interesting and gives a good explanation for something that many of us have encountered: an egg toss. #engmech

[Mark Johnson @MrQuackTactics]

@johnsonc0681 That was helpful. Thanks. #engmech

[Mark Johnson @MrQuackTactics]

http://t.co/g76MQj79m1 Good review of the basics of planar motion. #engmech

[Mark Johnson @MrQuackTactics]

Here's a good example problem solved using kinetic energy. http://t.co/zbrl2q3atS #engmech

[Mark Johnson @MrQuackTactics]

@billmill3131 With a radius of 3,959 miles, I would guess that the correct answer is: a lot. #engmech

[Mark Johnson @MrQuackTactics]

@M_Menkabo @YouTube That's a good example of a bar mechanism. #engmech

[Mark Johnson @MrQuackTactics]

http://t.co/IziNR9h8Xw Here's a website that explains centers of rotation plainly. Hope it helps. #engmech

[Mark Johnson @MrQuackTactics]

@rousha23 Does the inst. center of rotation need to be equidistant from the points that are rotating? #engmech

[Mark Johnson @MrQuackTactics]

@Zamzowm0574 If you think about it, there are two axes of rotation that are perpendicular to one another in this example. #engmech

[Mark Johnson @MrQuackTactics]

http://t.co/OXNVar817F Here's a good website that has formulas and some explanations for moment of inertia. Enjoy. #engmech

[Mark Johnson @MrQuackTactics]

@abdoll_uwstout Thanks for the sheet. It has all the formulas in one place for the rotation of different distributions of mass. #engmech

[Mark Johnson @MrQuackTactics]

@Sliebelt86 Cool video. It helps in understanding how different shapes act in relation to one another. #engmech

[Mark Johnson @MrQuackTactics]

@esterholmj0155 I would think potential energy to both. The moon's gravity and earth's gravity would both have P.E. #engmech

[Mark Johnson @MrQuackTactics]

@Rushaydaa0784 This certainly explains the concepts in a simple manner. It's a good video. #engmech