A cable used to lift heavy materials like steel I-beams must be strong enough to resist breaking even under a load of 1.8 106 N. For safety the cable must support twice that load.?

To ensure safety, the cable must be able to support a load of at least twice the maximum expected load of 1.8 x 10^6 N, which totals 3.6 x 10^6 N. This safety factor accounts for potential additional stresses and ensures that the cable can handle unexpected loads without breaking. Therefore, the cable must be designed and tested to safely handle this increased load capacity.