Testing apparatus and methods for measuring forces between objects

A testing apparatus, comprising:

• a base;
• a table mounted to the base through a plurality of columns, the table comprising a first opening, a second opening, and a beam separating the first opening and the second opening;
• a stage mounted to the base, the stage positioned inwardly of the plurality of columns;
• a central target arrangement comprising:
• a pair of masses,
• a target coupled to the pair of masses, and
• a target housing mounted to the table above the beam through one or more brackets coupled to the table and a rod extending into the beam;
• a detector configured to recognize the target;
• a first spinner tower comprising a first rotatable mass, the first spinner tower coupled to the stage and extending through the first opening on a first side of the target housing, wherein the first rotatable mass is supported independently of the target and the pair of masses;
• and
• a second spinner tower comprising a second rotatable mass, the second spinner tower coupled to the stage and extending through the second opening on a second side of the target housing.