According to the principal of wave refraction, when light from the atmosphere enters a medium of greater density at an oblique angle its a. velocity speeds up but angle remains the same b. velocity remains the same but angle changes c. velocity slows down but angle remains the same d. velocity slows down and angle changes

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?