An object is moving in one dimension. The frame of reference has an origin and its one axis is marked in units representing centimeters (cm): –5, –4, –3, –2, –1, 0, 1, 2, 3, 4, 5. What is the object’s displacement when it moves from –3 to 4 along the axis?

Olympic skier tina maze skis down a steep slope that descends at an angle of 30∘ below the horizontal. the coefficient of sliding friction between her skis and the snow is 0.10. i found maze's acceleration which is 4.1 m/s^2. but how do you determine maze's speed 4.0 s after starting?