Suppose you have a stack of 17 identical steel bars (steel bars have a mass of 1.00kg each). You are required to pull out bar number 16 from the stack (counting from the top of the stack down). Assuming that your assistant holds all other bars in place.   If the coefficient of friction between steel and steel is 0.750, how hard do you have to pull (in N)?

A 200 N sign hangs from the middle of a cable between two buildings. The ends of each cable are attached to each building at the same height. The cable cannot exceed 1500 N without breaking. Find the minimum angle that the cable can make from the horizontal.

An elevator has a mass of 200kg. An average person has of 40 kg. The elevator must accelerate upward at 3 m/s^2. If the elevator cable is capable of supporting 6500 N of tension before it breaks. What is the maximum number of people you could have on board?

A heavy sled is being pulled by two people, as shown in the figure. The coefficient of static friction between the sled and the ground is µs = 0.603, and the kinetic friction coefficient is = 0.403. The combined mass of the sled and its load is m = 336 kg. The ropes are separated by an angle o = 25.0°, and they make an angle 0 = 31.1° with the horizontal. Assuming both ropes pull equally hard, what is the minimum rope tension required to get the sled moving? minimum rope tension: N If this rope tension is maintained after the sled starts moving, what is the sled's acceleration? acceleration: m/s2