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Another way of saying sliding friction is to say the coefficient of kinetic friction" It is the friction you get once an object is already moving against a stationary object.
example if you are sitting on a sliding board and are at the top.
friction between your pants and the sliding board is called static friction.
is more of a friction force then when you push off then the static friction turns into kinetic friction which is the force of friction between your pants sliding down the board and the stationary board. Kinetic friction generally is less than static friction
example if you are sitting on a sliding board and are at the top.
friction between your pants and the sliding board is called static friction.
is more of a friction force then when you push off then the static friction turns into kinetic friction which is the force of friction between your pants sliding down the board and the stationary board. Kinetic friction generally is less than static friction
Tue, 09 Feb 2010 04:41:53 GMT
Dry friction (also known as Coulomb friction) is the kind of friction to which we refer with the formula "F mu*N". This involves two interacting surfaces, which are basically "dry". I.e. not involving any significant lubricating fluid.
friction can be both a force of constraint (static friction or traction), or a force which dissipates heat due to the sliding (sliding friction or kinetic friction). Dry friction is only dependent on if the surfaces are static or sliding.
force doesn't depend on how fast the sliding occurs.
is one big difference between dry friction types and friction involving fluids. To discuss further: 1.
friction. The coefficient is mu_s. F=mu_s*N gives you the maximum value of the static friction force.
force of static friction will oppose what ever motion is induced by the other forces, until it reaches its maximum value.
friction NEVER dissipates energy as heat. 2. Kinetic friction.
coefficient is mu_k. Typically mu_k is smaller than mu_s.
coefficients only depend on the roughness nature of the surfaces in contact, not on velocity or normal force. F=mu_k*N tells you the actual value for what friction opposes the sliding. Sliding friction is the type of dry friction which dissipates energy as heat.
to discuss fluid drag.
drag is the general term.
drag, air resistance, air friction are all phrases which mean the same, with one condition that the fluid involved is air (as opposed to water or oil and other options). Fluid drag does depend on velocity. It is proportional to either the square of velocity or directly proportional to velocity, depending on flow conditions.
laminar flow conditions, it is proportional to velocity relative to the fluid, and is named "Stokes Drag". For turbulent flow conditions, it is proportional to the square of velocity relative to the fluid and is named "Newton Drag". To discuss further: 1.
drag occurs at slow speeds, where viscosity effects dominate (typically fluids such as oil). Stokes drag can be given by the formula F -b*v, where b is a constant depending on geometry and fluid viscosity. 2.
drag occurs at fast speeds or in less viscous fluids (such as water or air), where impacting pressure effects dominate.
drag can be given by the formula F=1/2*Cd*rho*A*v^2, where Cd is the drag coefficient (depending on shape), rho is the fluid density, and A is the effective cross sectional area.
regimes of drag are forces which dissipate energy into heat.
does the drag force act as a force of constraint on stationary objects.
friction can be both a force of constraint (static friction or traction), or a force which dissipates heat due to the sliding (sliding friction or kinetic friction). Dry friction is only dependent on if the surfaces are static or sliding.
force doesn't depend on how fast the sliding occurs.
is one big difference between dry friction types and friction involving fluids. To discuss further: 1.
friction. The coefficient is mu_s. F=mu_s*N gives you the maximum value of the static friction force.
force of static friction will oppose what ever motion is induced by the other forces, until it reaches its maximum value.
friction NEVER dissipates energy as heat. 2. Kinetic friction.
coefficient is mu_k. Typically mu_k is smaller than mu_s.
coefficients only depend on the roughness nature of the surfaces in contact, not on velocity or normal force. F=mu_k*N tells you the actual value for what friction opposes the sliding. Sliding friction is the type of dry friction which dissipates energy as heat.
to discuss fluid drag.
drag is the general term.
drag, air resistance, air friction are all phrases which mean the same, with one condition that the fluid involved is air (as opposed to water or oil and other options). Fluid drag does depend on velocity. It is proportional to either the square of velocity or directly proportional to velocity, depending on flow conditions.
laminar flow conditions, it is proportional to velocity relative to the fluid, and is named "Stokes Drag". For turbulent flow conditions, it is proportional to the square of velocity relative to the fluid and is named "Newton Drag". To discuss further: 1.
drag occurs at slow speeds, where viscosity effects dominate (typically fluids such as oil). Stokes drag can be given by the formula F -b*v, where b is a constant depending on geometry and fluid viscosity. 2.
drag occurs at fast speeds or in less viscous fluids (such as water or air), where impacting pressure effects dominate.
drag can be given by the formula F=1/2*Cd*rho*A*v^2, where Cd is the drag coefficient (depending on shape), rho is the fluid density, and A is the effective cross sectional area.
regimes of drag are forces which dissipate energy into heat.
does the drag force act as a force of constraint on stationary objects.
Tue, 09 Feb 2010 04:58:24 GMT