Surface 1 : Surface 2: Time Time between K / m = between Time impacts , 1/2 V 2 Time impacts , At K / m = 1/2 V 2 Impact [s] [s ] [m/s] [J/kg ] Impact [s] [s] [m/s] [J/kg ] Note : this cell will contain the speed the ball Note : this cell the will contain the ground after time between impact 1 which impact 1 and s the same 2; the time of speed the ball bounce 1 (see hits the ground Figure 1.1 with before above ) impact 2 N 2 3 4 4 6 6 7 8 8 9 9 10 10 11 17 12 12