What behavior is characteristic of surface tension forces__________________?
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Answer: A. acts in the plane of the interface normal to any line in the surface
Explanation
Surface tension forces pull liquid molecules inward, creating a tangential tension along the fluid interface. This force acts directly in the plane of the liquid surface and normal to any imaginary dividing line. Molecular cohesion at the liquid boundary is responsible for maintaining this directional surface tension force. Surface tension is quantified as force per unit length acting along the surface of a liquid. It allows small insects to walk across water and causes droplets to form nearly spherical shapes. Temperature increases generally reduce surface tension because thermal agitation weakens molecular cohesion.
Fluid mechanics engineers account for surface tension in capillary tube flow and droplet formation. Detergents lower water surface tension to improve cleaning penetration in fabrics and surfaces. Biological systems rely on surface tension phenomena in pulmonary alveoli respiration mechanics. Option B confuses surface tension with capillarity, which is a secondary effect caused by surface tension. Option C describes curvature dependence, but the primary mechanical definition involves interface plane forces. Option D states the temperature trend backward, as surface tension decreases with rising temperature.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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