Question

a 1000 kg lift is tied with a metallic wire of maximum safe stress of 1.4*10^8 Nm^2.if the maximum acceleration of the lift is 1.2ms-^2,the the minimum of the wire is?

Answer 1

tension in wire = T= 1000 (9.8 + 1.2) = 11000N
maximum stress = T/ λr min² = 110000 x 7 /22 x r min²

r min² = 50²/ (10⁴)²

minimum radius = 50 x 10⁻⁴

minimum diameter= 2 x rmin
= 2 x 50 x 10⁻⁴
= 100 x 10⁻⁴m
= 0.01m