B$)$ A $2-$kg object accelerates as a net external force is applied to it$.$ During the $5-$second interval that the force is applied, the object's velocity changes from $3\frac{m}{s}$ east to $7\frac{m}{s}$ west. $(3$ points$)$

$=0$

$3\frac{m}{s}$

$5$ seconds later:

${}^{-}$

Several students discussing the impulse on this object state the following:

Andre: "The impulse is equal to the change in momentum, which is $(2kg)(3\frac{m}{s}+7\frac{m}{s})=20kg*\frac{m}{s}."$

Bela: "But the change in velocity is $4\frac{m}{s}.$ We multiply by the mass to get the change in momentum, and also the impulse, which is $8kg*\frac{m}{s}."$

Carleton: "The change in momentum of this object during these $5$ seconds was $8kg*\frac{m}{s}$ so the impulse applied to this object during these $5$ seconds was $\frac{8}{5}kg*\frac{m}{s}."$

Dylan: "The impulse is the force F times the time t and since we don't know the force, we can't find the impulse for this situation."

Which, if any, of these three students do you agree with?

Andre $,$ Bela $$ Carleton $$ Dylan $$ None of them $$

Please explain your reasoning.