specifies the following for the testing of the helmet: a dummy head of mass 6.1 kg (specified in the related standard EN 960) in a test helmet is dropped onto a stationary anvil two impact speeds are used, of 5.42 m s-1 and 4.57 m s-1 the test requires that the deceleration experienced by the dummy head does not exceed 250 × g, where g is the acceleration due to gravity.
(i) Show that the heights from which the helmet and dummy head should be dropped in the tests are equivalent to the Standard. Show your working, and state any assumptions that you make.
(ii) Estimate the maximum force experienced by the head during an ‘acceptable' impact.