i am asked to create a bookshelf, and this is one of the parts. The recommended solution by my teacher is use the truss analysis. Can someone guide me on this?

Samir watches a 100-minute movie on his spaceship. maria's spaceshipe flies in the same direction as samir's spaceship but she observes his move to last 125 minutes and his spaceship to be 40 m long. how long does samir observe his own spaceship to be? according to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does marias voyage take according to samir?

By definition a socially healthy person has access to clean water in adequate living space and makes an effort to recycle

An elevator is initially moving upward at a speed of 12.60 m/s. the elevator experiences a constant downward acceleration of magnitude 3.60 m/s2 for 2.97 s.