PHYS 117 Chapter Notes - Chapter 9: Tennis Ball, Net Force, Arteriosclerosis
Document Summary
Four states of matter: solids, liquids, gases, and plasmas. Crystalline solids have atoms in an ordered structure. Plasma: highly ionized matter containing equal amounts of positive and negative charges. The specifc gravity of a substance is the ratio of its density to the density of water at 4 c . The force exerted by a fluid on an object is always perpendicular to the surfaces of the object. Force is a vector and pressure is a scalar. Stress: the force per unit area causing a deformation. Tensile stress: force perpendicular to cross-section; ratio of the magnitude of the external force to the cross-sectional area. Tensile strain: ratio of the change in length to the original length. Young"s modulus, y, is the constant of proportionality. Elastic limit: a material subjected to a stress beyond this limit normally doesn"t return to original length when external force is removed. Ultimate strength: the greatest stress the substance can withstand without breaking.
