Oxygen gas is used to fill a balloon and a short time later the balloon is observed to only be half full. Explain this observation. A) The balloon leaks and the temperature went down. B) More oxygen was added to the balloon and the temperature went up. C) The pressure outside the balloon went down and the pressure inside went down. D) The pressure outside the balloon went down and the temperature inside went up.

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.