\text { A thin glass sheet can just carry a mass of } 5.5 ~kg \text {. The sheet was raised with an increasing acceleration } \text { with an object on it and was found to breakdown when the acceleration equals } 1.2 ~m / sec \text {. What is the mass } \text { of the object? Note: } g=9.8 ~m / sec^{2} \text {. }