4. Statically Determinate Cedar Post Force and Displacement A post carrying a load of 36 kN is made of cedar and has a diameter of 90 mm. The soil provides a frictional resistance along the post’s length that varies linearly from w = 0 at y = 0, to w = 6 kN/m at y = 1.5 m. The Cedar modulus of elasticity is 6890 MPa. (a) Determine the force F acting at the bottom of the post to maintain equilibrium. (b) Determine the displacement of the top of the post relative to the bottom. You can neglect the weight of the post.

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?