Answer:
Explanation:
The bulldozer is moving the rocks as one system, the weigth for the complete system is:
From newton´s second law the acceleration can be related to the force by:
on the middle rock we have the force F12 from the first to the middle rock on the direction of movement and F32 from the las rock to the middle rock on the opposite direction of movement.
For the last rock to accelerate at the same rate it must be subjected to a force:
This equals the force F32 on the opposite direction. the resultant force on the middle rock to mantain this acceleration should be:
The sum of all the forces applied to the middle rock is:
Solving for F12: