reference:

- EJS Static and Kinetic Friction on Incline Plane Model by Francisco Esquembre and lookang http://weelookang.blogspot.sg/2014/04/ejs-static-and-kinetic-friction-on.html
- Sliding Down an Incline Plane Model by Francisco Esquembre http://www.compadre.org/osp/items/detail.cfm?ID=9973

EJSS Static and Kinetic Friction
on Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejss-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_friction/friction_Simulation.htmlsource: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_friction.zip author: Francisco Esquembre and recreated on EJSS by lookang |

EJSS
Static and Kinetic Friction on Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejss-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_friction/friction_Simulation.htmlsource: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_friction.zip author: Francisco Esquembre and recreated on EJSS by lookang |

EJS Static and Kinetic Friction on
Incline Plane Model http://weelookang.blogspot.sg/2014/04/ejs-static-and-kinetic-friction-on.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_model_SlidingDownAnInclinedPlanewee.jar author: Francisco Esquembre and remixed by lookang |

## Model description by Paco:

### Block sliding down an inclined plane

A stone block is lying on an inclined plane.Initially, the component of gravity along the plane surface,

The model assume the mass of the block is m = 1 kg,

where W
is the weight and g
is the gravitational constant of 9.81 m/s^2

In equilibrium,

In this model,

However, the modulus of this force

In this model, when velocity = 0,

since fstatic cannot be greater
than mgsin(θ) nor μstaticN

When the user increases the slope of the plane

In this model, when velocity not equal to zero,

The force caused by static friction is replaced by a (smaller) force of dynamic (or kinetic) friction

## Condition for hint:

if (velocity = 0 and and only and totalForce(t,x,v) = 0), hint statetext = " in equilibrium,..."else if (velocity = 0 and and only and totalForce(t,x,v) != 0) hint statetext = " NOT in equilibrium,..."

else if (velocity != 0) hintstatetext= " NOT in equilibrium and in motion..."

## Determine direction of motion and direction of friction

if (v===0){directionOfMotion=0;

}

else if (v<0){

directionOfMotion=-1;

}

else if (v>0){

directionOfMotion=+1;

}

## Custom function:

function totalForce(time,position,velocity) {

if (velocity!==0) return
Ft+directionOfMotion*dynamicFriction; // in motion

return Math.max(0,staticFriction+Ft); // not in
motion

}

## changes made:

- re-implemented on EJSS
- added a scaleforce to draw the forces to user's choice
- made the static and kinetic friction drawn from same vector as visible===true was buggy
- added more hints to make explicit in equilibrium and not in equilibrium when net force.
- made the color dynamic with change in static to kinetic
- added paco as co-author as the EJS codes came from the man :)