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Mercury in a glass flask is a good example of the effects of the ratio between cohesive and adhesive forces. Because of its high cohesion and low adhesion to the glass, mercury does not spread out to cover the bottom of the flask, and if enough is placed in the flask to cover the bottom, it exhibits a strongly convex meniscus, whereas the ...
The cohesive forces that bind the molecules together are van der Waals forces, dipole–dipole interactions, quadrupole interactions, π–π interactions, hydrogen bonding, halogen bonding, London dispersion forces, and in some molecular solids, coulombic interactions.
There are two primary mechanisms in play. One is an inward force on the surface molecules causing the liquid to contract. [2] [3] Second is a tangential force parallel to the surface of the liquid. [3] This tangential force is generally referred to as the surface tension. The net effect is the liquid behaves as if its surface were covered with ...
Van der Waals forces are often among the weakest chemical forces. For example, the pairwise attractive van der Waals interaction energy between H atoms in different H 2 molecules equals 0.06 kJ/mol (0.6 meV) and the pairwise attractive interaction energy between O atoms in different O 2 molecules equals 0.44 kJ/mol (4.6 meV). [9]
The forces acting on a body add as vectors, and so the total force on a body depends upon both the magnitudes and the directions of the individual forces. [ 23 ] : 58 When the net force on a body is equal to zero, then by Newton's second law, the body does not accelerate, and it is said to be in mechanical equilibrium .
where stress is the force causing the deformation divided by the area to which the force is applied and strain is the ratio of the change in some parameter caused by the deformation to the original value of the parameter. Since strain is a dimensionless quantity, the units of will be the same as the units of stress. [2]
Studies have shown that people in cohesive groups have reported more satisfaction than members of a noncohesive group. [39] [40] [41] This is the case across many settings, including industrial, athletic, and educational settings. Members in cohesive groups also are more optimistic and suffer less from social problems than those in non-cohesive ...
Tension (as a transmitted force, as an action-reaction pair of forces, or as a restoring force) is measured in newtons in the International System of Units (or pounds-force in Imperial units). The ends of a string or other object transmitting tension will exert forces on the objects to which the string or rod is connected, in the direction of ...