Determine the up stretched length of DR to hold the 40 kg cr

Determine the up stretched length of DR to hold the 40 kg crate in the position shown. Take k - 180 N/m.

Solution

Stretched length of DB = sqrt(2^2+3^2) = 3.606 m

Tdb*2/3.606 + Tdb*3/3.606 = 40*9.8

Tdb = 40*9.8*3.606/5 = 282.7 N

stretch = Tdb/k = 282.7/180 = 1.571 m

unstretched length = 3.606-1.571 = 2.035 m answer