# Mass

```model Mass "Sliding mass with inertia"
parameter SI.Mass m(min = 0, start = 1) "Mass of the sliding mass";
parameter StateSelect stateSelect = StateSelect.default "Priority to use s and v as states"

extends Translational.Interfaces.PartialRigid(L = 0, s(start = 0, stateSelect = stateSelect));

SI.Velocity v(start = 0, stateSelect = stateSelect) "Absolute velocity of component";
SI.Acceleration a(start = 0) "Absolute acceleration of component";
equation
m * a = flange_a.f + flange_b.f;
a = der(v);
v = der(s);

annotation (
Documentation(info = "<html>\n<p>\nSliding mass with <em>inertia, without friction</em> and two rigidly connected flanges.\n</p>\n<p>\nThe sliding mass has the length L, the position coordinate s is in the middle.\nSign convention: A positive force at flange flange_a moves the sliding mass in the positive direction.\nA negative force at flange flange_a moves the sliding mass to the negative direction.\n</p>\n\n</html>"),
Icon(
coordinateSystem(
preserveAspectRatio = true,
extent = {
{-100, -100},
{100, 100}}),
graphics = {
Line(
points = {
{-100, 0},
{100, 0}},
color = {0, 127, 0}),
Rectangle(
extent = {
{-55, -30},
{56, 30}},
fillPattern = FillPattern.Sphere,
fillColor = {160, 215, 160},
lineColor = {0, 127, 0}),
Polygon(
points = {
{50, -90},
{20, -80},
{20, -100},
{50, -90}},
lineColor = {95, 127, 95},
fillColor = {95, 127, 95},
fillPattern = FillPattern.Solid),
Line(
points = {
{-60, -90},
{20, -90}},
color = {95, 127, 95}),
Text(
extent = {
{-150, 85},
{150, 45}},
textString = "%name",
lineColor = {0, 0, 255},
fillColor = {110, 210, 110},
fillPattern = FillPattern.Solid),
Text(
extent = {
{-150, -45},
{150, -75}},
textString = "m=%m",
fillColor = {110, 221, 110},
fillPattern = FillPattern.Solid,
fontSize = 0)}),
Diagram(
coordinateSystem(
preserveAspectRatio = true,
extent = {
{-100, -100},
{100, 100}}),
graphics = {
Line(
points = {
{-100, 0},
{-55, 0}},
color = {0, 127, 0}),
Line(
points = {
{55, 0},
{100, 0}},
color = {0, 127, 0}),
Rectangle(
extent = {
{-55, -30},
{55, 30}},
fillPattern = FillPattern.Sphere,
fillColor = {255, 255, 255}),
Polygon(
points = {
{50, -90},
{20, -80},
{20, -100},
{50, -90}},
lineColor = {128, 128, 128},
fillColor = {128, 128, 128},
fillPattern = FillPattern.Solid),
Line(points = {
{-60, -90},
{20, -90}}),
Line(points = {
{-100, -29},
{-100, -61}}),
Line(points = {
{100, -61},
{100, -28}}),
Line(points = {
{-98, -60},
{98, -60}}),
Polygon(
points = {
{-101, -60},
{-96, -59},
{-96, -61},
{-101, -60}},
fillPattern = FillPattern.Solid),
Polygon(
points = {
{100, -60},
{95, -61},
{95, -59},
{100, -60}},
fillPattern = FillPattern.Solid),
Text(
extent = {
{-44, -41},
{51, -57}},
textString = "Length L",
lineColor = {0, 0, 255}),
Line(points = {
{0, 30},
{0, 53}}),
Line(points = {
{-72, 40},
{1, 40}}),
Polygon(
points = {
{-7, 42},
{-7, 38},
{-1, 40},
{-7, 42}},
fillPattern = FillPattern.Solid),
Text(
extent = {
{-61, 53},
{-9, 42}},
textString = "Position s",
lineColor = {0, 0, 255})}));
end Mass;

```