The radius ofa copper bar is 4 mm. What force is required to stretch the rod by 20% of its length, assuming that the elastic limit is not exceeded? Y = 12 × 1010 N m2

Many caterpillars construct cocoons from silk, one of the strongest naturally occurring materials known. Each thread is typically 2.0 µm in diameter, and the silk has a Young's modulus of 4.0 × 10⁹ N/m². Assuming that there is no appreciable space between the parallel strands, how many strands N would be needed to make a rope 8.2 m long that would stretch only 1.02 cm when supporting a pair of 91-kg mountain climbers? N = Again assuming that there is no appreciable space between the parallel strands, what would be the diameter d of the rope? strands d = cm

A 5.0 x 102 N object is hung from the end of a wire of cross-sectional area 1x106 cm?. The wire stretches from its original length of 200.00 cm to 200.50 cm. What is the stress on the wire? A 5.0 x 10^8 N/m2 (B) 1.0 x 10^8 N/m2 (c) 5.0 x 102 N/m² D 1.0 x 10^6 N/m2

A 2m long, 1mm diameter wire is suspended from the ceiling. Hanging a 4.5kg mass from the wire streches the wire's length by 1mm. What is the Young's modulus for this wire? I just need teh answer please.