5. Determine the critical stress in the tube column shown below. The column has a height of 28 feet; it has a fixed connection at the top and a pinned connection at the bottom. The material has a modulus of elasticity of 29 x10³ ksi. 6" 5" 5" 6"

As an engineer working for the oil-based multinational company Petronas, you are re- checking the calculations done by the consultants as shown in Figure 3. However, upon submission, your chief engineer told you to sit down and asks you to re-calculate the following back to check if you really understood the calculations; (a) Find the distance ỹ to the centroid of the beam's cross-sectional areas and calculate the moment of inertia about the x'axis. (b) What is the moment of inertia of the beam's cross sectional area about the y- axis? (c) Your chief engineer further asks "It is often the case that the moment of an inertia for an area is known about an axis passing through its centroid. What can then be said about the moment of inertia of the same area about a corresponding parallel axis?" 50 mm 50 mm 300 mm 100 mm -200 mm Figure 3

KINDLY SHOW YOUR SOLUTIONS AND CHOOSE THE CORRECT ANSWERS.

** Please label the question answers so I can understand better! Thanks! Scenario: A chair with a mass of 20.0 kg is attached to one end of a frictionless pulley system via a strong massless rope. The other end of the rope is attached to a steel water tank sitting on a flat horizontal concrete surface (see the image to the right). The coefficient of static friction between steel and concrete is 0.45 and the coefficient of kinetic friction between the surfaces is 0.30. The water tank, which is full of water, has sprung a leak. The combined mass of the water and the tank is 500 kg. This mass slowly decreases as the water leaks from the hole. You (i.e. my mass is 55.7 KG) are sitting at rest in the seat. You and the seat will remain at rest as long as the force of static friction is strong enough to hold you. Task: LET [DOWN] and [RIGHT] be positive. Using your knowledge of physics, determine the following: 1. As soon as the chair begins to move, static friction between the steel…