George is trying to determine the effect of air resistance on his automobile. he finds that force (f) in newtons (a newton being kg⋅m/s2), depends on the speed at which his car travels (v), in m/s, the air surface area (a) of his car's front, in m2, the density of the air around his car (d), in kg/m3 and a unitless friction coefficient (χ). the friction coefficient is similar to that used in determining the force due to kinetic friction.

Diego is trying to lift a piano to the second floor of his house. diego uses a pulley system and gives a big lift to the piano. the piano moves upward, then stops, and then it starts to fall to the ground. which list best describes the forces on the piano in the proper order? a.positive force, balanced force, negative force b.negative force, balanced force, positive force c.positive force, unbalanced force, negative force d. negative force, unbalanced force, positive force