यदि एक बंद-कुंडलित पेचदार कमानी (helical spring) में सक्रिय कुंडलियों की संख्या 8 है और तार का व्यास 3 mm है, तो इसकी ठोस लंबाई _________ mm होगी।

When a bar of length l and uniform cross-section is rigidly fixed at the upper end and hangs freely, the total elongation produced in the bar due to its own weight is given by (where w = weight per unit volume and E = Modulus of Elasticity):

The hoop stress set up in a thin cylinder subjected to internal fluid pressure is: