15. While rummaging in her backpack for her cell phone, Sally's Mini-Cooper rear ends Joey's Suburban. Sally's car is totaled while the suburban is fine. If Sally's car hit the suburban with 30 N of force, how
much force did Joey's car exert on Sally's? (a) more than 30 N, (b) less than 30 N. (C) exactly 30 N.

Multiple choice. choose the one alternative that best completes the statement or answers the question. 1) if the force on an object is in the negative direction, the work it does on the object must be 1) a) negative. b) positive. c) the work could be either positive or negative, depending on the direction the object moves. 2) a truck has four times the mass of a car and is moving with twice the speed of the car. if kt and kc refer to the kinetic energies of truck and car respectively, it is correct to say that 2) a) kt = 16kc . b) kt = 1 2 kc. c) kt = kc . d) kt = 2kc . e) kt = 4kc . 3) you and your friend, who weighs the same as you, want to go to the top of the eiffel tower. your friend takes the elevator straight up. you decide to walk up the spiral stairway, taking longer to do so. compare the gravitational