change in momentum of car is given as
[tex]\Delta P = P_f - P_i[/tex]
here we have
[tex]\Delta P = m(v_f - v_i)[/tex]
given that
m = 2000 kg
[tex]v_f = 0[/tex]
[tex]v_i = 60 m/s[/tex]
now we have
[tex]\Delta P = 2000(0 - 60) [/tex]
[tex]\Delta P = - 1.2 \times 10^5 kg m/s[/tex]