An overnight rainstorm has caused a major roadblock. three massive rocks of mass m1=584 kg, m2=838 kg, and m3=322 kg have blocked a busy road. the rocks are lined up from left to right in the order m1, m2, and m3. the city calls a local contractor to use a bulldozer to clear the road. the bulldozer applies a constant force to m1 in order to slide the rocks off the road. assuming the road is a flat, frictionless surface and the rocks are all in contact, what force, , must be applied to m1 to slowly accelerate the group of rocks from the road at 0.250 m/s2?