dockworker loading crates on a ship finds that a 26-kg crate, initially at rest on a horizontal surface, requires a 70-N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 53 N is required to keep it moving with a constant speed. Find the coefficients of static and kinetic friction between crate and floor.

Taws Assignment A mother tows her daughter on a sled on level ice. The friction between the sled and the ice is negligible, and the tow rope makes an angle of e to the horizontal. The combined mass of the sled and the child is M. The sled has an acceleration in the horizontal direction of magnitude a . As we will learn to justify in a few weeks, the child and sled can be treated in this problem as if they comprised a single particle. M a. a) Calculate the tension, T, in the rope and the magnitude of the normal force, N, exerted by the ice on the sled. Briefly describe how you model the problem and your strategy for solving this problem. Show all relevant free body diagrams. b) Calculate the new tension, T, in the rope and the magnitude of the new normal force, N', exerted by the ice on the sled. Briefly describe any changes you need to make to your previous model and strategy. Show all relevant free body diagrams.

Albert presses a book against a wall with his hand. As Albert gets tired, he exerts less force, but the book remains in the same spot on the wall. Classify each force on the book as increasing, decreasing, or not changing in magnitude when Albert reduces the force he is applying to the book. Not every classification must be used.   Is each one of the following increasing, decreasing or not changing: 1) weight of the book 2) maximum static frictional force of the wall on the book 3) NORMAL FORCE OF WALL ON THE BOOK 4)frictional force of wall on the book

Learning Goal: An object experiences three forces (and only three forces): 28N in the positive x-direction, 30N in the negative y-direction, and 72N at an angle of 35° above the negative x-axis. What is the magnitude of the net force acting on this object?