three different objects, all with different masses, are initially at rest at the bottom of a set of steps. each step is of uniform height ????d . the mass of each object is a multiple of the base mass mm : object 1 has mass 4.90m4.90⁢m , object 2 has mass 1.46m1.46⁢m , and object 3 has mass mm . when the objects are at the bottom of the steps, define the total gravitational potential energy of the three-object system to be zero. each answer requires the numerical coefficient to an algebraic expression that uses some combination of the variables mm , ????g , and ????d , where ????g is the acceleration due to gravity. enter only the numerical coefficient. (example: if the answer is 1.23m????????1.23⁢m⁢g⁢d , just enter 1.23)