28. The shaft shown in Figure P5-28 is supported by bear- ings at each end, which have bores of 20.0 mm. Design the shaft to carry the given load if it is steady and the shaft is stationary. Make the dimension a as large as pos- sible while keeping the stress safe. Determine the required d = 20mm D = ? R = ?| 5.4 kN d=20mm Length not to scale -a = ?- +а= a = ? + -125 mm- -250 mm- FIGURE P5-28 (Problems 28, 29, and 30)

12. Compute the estimated actual endurance limit for SAE 4130 WQT 1300 steel bar with a rectangular cross sec- tion of 20.0 mm by 60 mm. It is to be machined and subjected to repeated and reversed bending stress. A reli- ability of 99% is desired.

28. The shaft shown in Figure P5-28 is supported by bear- ings at each end, which have bores of 20.0 mm. Design the shaft to carry the given load if it is steady and the shaft is stationary. Make the dimension a as large as pos- sible while keeping the stress safe. Determine the required d = 20mm D = ? R = ?| 5.4 kN d=20mm Length not to scale -a = ?- +а= a = ? + -125 mm- -250 mm- FIGURE P5-28 (Problems 28, 29, and 30)

2. A strut in a space frame has a rectangular cross section of 10.0 mm by 30.0 mm. It sees a load that varies from a tensile force of 20.0 kN to a compressive force of 8.0 kN.

find stress at Q

I had a theoretical question about attitude determination. In the attached images, I gave two axis and angles. The coefficient of the axes are the same and the angles are the same. The only difference is the vector basis. Lets say there is a rotation going from n hat to b hat. Then, you introduce a intermediate rotation s hat. So, I want to know if the DCM produced from both axis and angles will be the same or not. Does the vector basis affect the numerical value of the DCM? The DCM formula only cares about the coefficient of the axis and the angle. So, they should be the same right?

3-15. A small fixed tube is shaped in the form of a vertical helix of radius a and helix angle y, that is, the tube always makes an angle y with the horizontal. A particle of mass m slides down the tube under the action of gravity. If there is a coefficient of friction μ between the tube and the particle, what is the steady-state speed of the particle? Let y γ 30° and assume that µ < 1/√3.

The plate is moving at 0.6 mm/s when the force applied to the plate is 4mN. If the surface area of the plate in contact with the liquid is 0.5 m^2, deterimine the approximate viscosity of the liquid, assuming that the velocity distribution is linear.

3-9. Given that the force acting on a particle has the following components: Fx = −x + y, Fy = x − y + y², F₂ = 0. Solve for the potential energy V. -