We have common experience that a thin thread breaks if pulled at its ends. Also a thin metalic wire, when pulled at the ends elongates and then contracts, when released. What do you mean by elasticity?

We have common experience that a thin thread breaks if pulled at its ends. Also a thin metalic wire, when pulled at the ends elongates and then contracts, when released. A lift is tied with thick iron wires and its mass is 1000kg . What should be the minimum diameter of the wire if the maximum acceleration of the lift is 1.2m/s^2 and maximum safe stress of the wire is 1.4xx10^8N/m^2 (g= 9.8m/s^2 )

In Geiger-Marsden Scattering experiment alpha per ticles of 5.5 MeV is allowed to fall on a thin gold foll of thickness 2.1 * 10^-7m. In the above graph nearly 10^7 particles were detected when scattering angle is Zero. What do you under stand by it?