The core of an optical fiber has an index of refraction of 1.35 , while the index of refraction of the cladding surrounding the core is 1.21 . What is the critical angle θc for total internal reflection at the core‑cladding interface?

Agymnast dismounts off the uneven bars in a tuck position with a radius of 0.3m (assume she is a solid sphere) and an angular velocity of 2rev/s. during the dismount she stretches out into the straight position, with a length of 1.5m, (assume she is a uniform rod through the center) for her landing. the gymnast has a mass of 50kg. what is her angular velocity in the straight position?

Ahot-air balloonist, rising vertically with a constant speed of 5.00 m/s releases a sandbag at the instant the balloon is 40.0 m above the ground. after it is released, the sandbag encounters no appreciable air drag. compute the velocity of the sandbag at 0.250 s after its release.

Ms.hidalgo opens the door to her classroom. her classroom is 60 degrees and the air outside is 80. predict what will happen using your knowledge of how heat flows.