Athin spherical glass shell in air is filled with an unknown liquid. a parallel light beam is incident on the shell, and it is observed that the light is brought to focus on the surface of the shell directly opposite. what is the refractive index of the liquid?

the anwser is "n=2" but i'm not sure how this was calculated. i was thinking of using snell's law and small angle approximation considering that this is a thin lens we're working with, but then again my brain doesn't physics very well so i have no idea if this should even be considered for this kind of question. !

Next a skier is pulled by a tow rope up a frictionless ski slope that makes an angle of 15 with the horizontal. the rope moves parallel to the slope with a constant speed of 0.69 m/s. the force of the rope does 800 3 of work on the skier as the skier moves a distance of 8.4 m up the incline. (a) if the rope moved with a constant speed of 2.2 m/s how much work would the force of the rope do on the skier as the skler moved a distance of 8.4 m up the incline? at what rate is the force of the rope doing work on the skier when the rope moves with a speed of (b) 0.69 m/s and (c) 2.2 m/s?

A- a of 8.00 cm a of 34.0 nc. a , -, a of 25.0 nc is on of a of 15.0 cm .be toto aof ? a) b) c) j d) e)

Acar travels 40m in 8 seconds find the car speed