Answer:
The net force is greater at the second situation as well as the acceleration due to the contribution of the second guy.
Step-by-step explanation:
Hello.
In this case, since the net force is computed via adding all the exerted forces on a body, for the first situation we can see that the net force equals the force provided by that guy when pulling, whereas in the second situation the net force equals the force of both of the guys pulling the car:
For the acceleration, we can see that applying an extra force (due to the second guy) turns out into a greater acceleration, that is why the car at the second situation reaches the tree whereas the other one does not.
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