A world's land speed record was set by Colonel John P. Stapp when in March 1954 he rode a rocket-propelled sle

A world's land speed record was set by Colonel John P. Stapp when in March 1954 he rode a rocket-propelled sled that moved along a track at 1020 km/h. He and the sled were brought to a stop in 1.4 s. (See Fig. 2-7). In g units, what acceleration did he experience while stopping?