Vo = I/m = 1.4 Nsec/0.75 kg = 1.866 m/sec
Eo = m/2Vo^2 = 1.866^20.375 = 2.61 joule
after 2 meters
E1 = Eo-0.202 = 2.61-0.4 = 2.21 joule
V1 = Vo√E1/Eo = 1.866√2.21/2.61 = 1.717 m/sec
22 = (1.866+1.717)t
t1 = 22 /(1.866+1.717) = 1.116 sec
a1 = -(1.866-1.717)/1.116 = -0.134 m/sec^2
after 4 meters
E2 = Eo-0.204 = 2.61-0.8 = 1.81 joule
V2 = Vo√E2/Eo = 1.866√1.81/2.61 = 1.554 m/sec
t2 = 22 /(1.717+1.554) = 1.223 sec
a2 = -(1.717-1.554)/1.223 = -0.133 m/sec^2
a = (a1+a2)/2 = -0.1335 m/sec^2
d(t) = Vot+a/2t^2
after 1,5 sec :
d = 1.8661.5-0.1335/2*2.25 = 2.65 m