An overnight rainstorm has caused a major roadblock. three massive rocks of mass m1=598kg, m2=796kg and m3=311kg have blocked a busy road. the city calls a local contractor to use a bulldozer to clear the road. the bulldozer applies a constant force to m1 to slide the rocks off the road. assuming the road is a flat frictionless surface and the rocks are all in contact, what force, fa must be applied to m1 to slowly accelerate the group of rocks from the road at 0.100m/s2. use the value found above fro fa to find the force f12 exerted by the first rock of mass 598kg on the middle rock of 769kg

Aspring has a relaxed length of 33 cm (0.33 m) and its spring stiffness is 6 n/m. you glue a 76 gram block (0.076 kg) to the top of the spring, and push the block down, compressing the spring so its total length is 15 cm. you make sure the block is at rest, then at time t=0 you quickly move your hand away. the block begins to move upward, because the upward force on the block by the spring is greater than the downward force on the block by the earth. calculate y vs. time for the block during a 0.09-second interval after you release the block, by applying the momentum principle in three steps each of 0.03-second duration.