Trick questions..
1. Both cars are subject to the same forces
(newtonian laws state forces come in pars, action/reaction)
So if the truck is being pushed by the car the car must be bing pushed by the truck.. The acceleration will not be the same because F=MA, and the truck has a bigger mass, so will have a smaller acceleration.
2. They both undergo the same momentum change. Becasue momentum is conserved, it cannot dispear it can only be transfered. So if the car loses lets say 200 newton meters/ seconds the truck must gain that and vice versa. Proportianally 200/car's original momenum is greater then 200/trucks original momentum becasue the truck has more momentum to begin with. But the total momentum change for both is equal.