Which of the following describes how the mechanical advantage of a simple machine affects the amount of force needed for work? A. By decreasing the distance over which the input force is applied, less force is needed to do the same amount of work. B. By decreasing the distance over which the input force is applied, more force is needed to do the same amount of work. C. By increasing the distance over which the input force is applied, more force is needed to do the same amount of work. D. By increasing the distance over which the input force is applied, less force is needed to do the same amount of work.

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next