Friction test. Multiple exposure image of apparatus measuring the dynamic coefficient of friction, or slipperiness, of a floor tile. The pendulum (lower right) sweeps across its surface and loses momentum on contact due to friction. This is measured on the scale seen at centre. Such measurements are useful in a safety capacity, assessing the suitability of workplace floor coverings, for example. CROWN COPYRIGHT UNDER LICENCE FROM THE HEALTH & SAFETY LABORATORY & CONTROLLER OF HER MAJESTY'S STATIONERY OFFICE