The weight of earth's atmosphere exerts an average pressure of 1.01 ✕ 105 pa on the ground at sea level. use the definition of pressure to estimate the weight of earth's atmosphere (in n) by approximating earth as a sphere of radius re = 6.38 ✕ 106 m and surface area a = 4πre2. hint n

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?