Q: An elastic wire is found to be elongated by 1 cm when a mass is gently hung from it. It extends by 3 cm more, when the attached mass is made to move uniformly in a horizontal circle performing 2 rev s-1. The length of the unstretched wire (in cm) is (Given, g = 9.81 ms-2)
Q: The pressure that has to be applied to the end of a steel wire of length 10cm to keep its length constant when its temperature is raised by 100°C is (for steel, Young’s modulus is 2 × 1011 Nm-2 and coefficient of thermal expansion is 11 × 10-5 K-1)
Q: Two wires are made of the same material and have the same volume. However, wire 1 has cross-sectional area A and wire 2 has cross-sectional area 3A. If the length of wire 1 increases by Δx on applying force F, then how much force is needed to stretch wire 2 by the same amount?
Q: One end of a horizontal thick copper wire of length 2L and radius 2R is welded to an end of another horizontal thin copper wire of length L are radius R. When the arrangement is stretched by applying forces at two ends, the ratio of the elongation in the thin wire to that in the thick wire is