In the frame where the tensor of inertia is diagonal calculate it for: 1. a uniform disc of mass m and radius r. 2. a uniform solid (not hollow) sphere of mass m and radius r. 3. a thin stick of length l and mass m, if the origin is at one end of the stick. 4. a thin stick of length l and mass m, if the origin is at the center of the stick.

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

Answermuch larger;

Ray 2 should cross through the focal point on the right side of the lens.

Well i am not very good at this but  i would be guessing 1hope i