$x= x_o+ v_o.t+0,5at^2$
$\Rightarrow v_o=-2(m/s), x_o=10(m), a=1(m/s^2)$
$P_o= m_o.v_o= -4(kg.m/s)$
Sau 5s, $x=0,5.5^2-2.5+10=12,5(m)$
$\Rightarrow \Delta x=12,5-10=2,5(m)$
$v=\sqrt{v_o^2+ 2a.\Delta x}= 3(m/s)$
$P=mv=3.2=6(kg.m/s)$
$\Rightarrow \Delta P=6-(-4)=10(kg.m/s)$
=> chọn A