Question

8 sharon is driving on a straight road she is driving north, and her speed is decreasing. if north is the positive direction, which of the following statements is accurate? her velocity is positive, and her acceleration is positive her velocity is negative, and her acceleration is negative her velocity is positive, and her acceleration is negative her velocity is negative, and her acceleration is positive

Explanation:

Step1: Determine the velocity sign

Since Sharon is driving north and north is the positive direction, velocity \(v>0\) (positive).

Step2: Determine the acceleration sign

Acceleration \(a=\frac{\Delta v}{\Delta t}\). Her speed (\(\vert v\vert\)) is decreasing. If \(v = +\vert v\vert\) and \(\vert v\vert\) is decreasing, then \(\Delta v<0\). So \(a=\frac{\Delta v}{\Delta t}<0\) (negative) as \(\Delta t>0\) (time is always increasing).

Answer:

Her velocity is positive, and her acceleration is negative.