Light beam is directed parallel to the axis of a hollow cylindrical tube. When the tube contains only air, the light takes 8.72 ns to travel the length of the tube, but when the tube is filled with a transparent jelly, the light takes 1.82 ns longer to travel its length. What is the refractive index of this jelly

An ideal spring has a spring constant (force constant) of 2500 n/m, is stretched 4.0 cm, how much elastic potential energy does it possess? (a) 3j (b) 0.00j (c) 1j (d) 2j (e) 4j

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

Thomas his older brothers, who own a junk yard, on the weekends to earn extra money. he likes to them push broken-down cars to the back of the junk yard because it makes him feel strong. last saturday, they pushed three cars with different weights, and he noticed he used different amounts of force for each one. the cars were the following weights: white car: 2,700 kg red car: 1,500 kg blue car: 2,100 kg think about how much force is needed to move each car. which correctly lists the cars in order from the most to least amount of force needed to move them? a) white, blue, red b) blue, red, white c) red, white, blue d) white, red, blue