Answer:
Force and Change in velocity
Explanation:
The contact time is the exact same, as they have hit eachother, rather than something.
The force is how hard they hit eachother, and due to the weight of each object, and the size, the mosquito has much less force.
The change in velocity is also unequal. While the mosquito gets squished, and is now getting thrown in the other direction, the truck is almost completely uneffected, and it's movement stays the same.
