1. The problem statement, all variables and given/known data A helium-filled balloon is tied to a 2.00-m-long, 0.0500-kg uniform string. The balloon is spherical with a radius of 0.400m. When released, it lifts a length h of string and then remains in equilibrium, as in the figure. Assuming envelope of the balloon has mass 0.250 kg and that the balloon raises a height less than the length of the string, determine the value of h. and A sealed spherical shell of diameter d is rigidly attached to a cart that is moving horizontally with an acceleration a to the right as shown in the picture. The sphere is nearly filled with a fluid having density ρ and also contains one small bubble of air at atmospheric pressure. a) When a = 0, determine the pressure at the center of the sphere. b) Now assume a ≠ 0, determine the pressure again at the center of the sphere. (Hint. Think of what water does in a glass when you accelerate it to the right or which way you feel the force when you accelerate your car. Don't forget you now have two forces.) I have no idea where to even begin with these two problems. Could someone please point me in the right direction?