For all problems where there are multiple forces acting on the same object, draw a freebody diagram (i.e. a diagram where each vector for each of the different forces is shown).
1. Consider an object of mass 10 kg hanging from a spring with a force law F=kx. The x in this case is the displacement from where the bottom of the spring would be if there were no mass attached to it. For this spring, k takes a value of 50 N/meter. Show where the location of the spring will be after the mass is attached to it, when it settles down to its equilibrium location.
2. Moe and Curley are in the park. Moe has a mass of 80 kg. Curley has a mass of 60 kg. More jumps off the jungle gym, from a height of 2 meters. As Moe jumps, Curley, who is standing on the ground begins to shove him with a force of 10 Newtons, and Curley continues to apply that constant force until Moe lands. What is Moe's horizontal displacement from his original location? What is Moe's speed when he hits the ground? What is the minimum possible value for Curley's coefficient of static friction if he does not move?
3. Suppose you can do a pushup in 0.3 seconds. Make an estimate of how high off the ground you lift yourself and your own mass. Assume constant acceleration during the pushup. Estimate the force that you must apply to do the pushup. Estimate the acceleration of the Earth do to doing the pushup.
4. A book on a table has a coefficient of static friction of 0.1 and a coefficient of kinetic friction of 0.05. The book has a mass on 1 kg. The table has a length of 3 m. Suppose you gently tilt the table until the book starts to slip, and then leave the angle of the book at that critical angle afterwards. How long will it take the book to slide to the end of the table?