A few butterflies and many moth species spin a silk case or cocoon prior to pupating, while others do not, instead going underground. A butterfly pupa, called a chrysalis, has a hard skin, usually with no cocoon.
4. tension - (physics) a stress that produces an elongation of an elastic physical body; the direction of maximum tension moves asymptotically toward the direction of the shear. natural philosophy, physics-the science of matter and energy and their interactions; his favorite subject was physics.
Tension force is a pulling force that acts on the body when it is hanged to objects like cable, chain, or string. It is also the stress force that pulls on the crust where 2 plates move apart. Tension force is usually denoted by T (sometimes also denoted as F sub t). This is the formula for tension force: T= wÂ± ma. Where, w is weight of the body, m for mass and a for acceleration of the moving body.