9. (3 points) which of the following graphs represent an object having zero acceleration? (a) (b) (c) (d) a)…

Explanation:

Step1: Recall acceleration - velocity - time relation

Acceleration $a=\frac{\Delta v}{\Delta t}$. Zero acceleration means constant velocity (slope of velocity - time graph is zero) or zero velocity.

Step2: Analyze graph a

Graph a shows a linearly increasing velocity. Slope of $v - t$ graph is non - zero. So, acceleration is non - zero.

Step3: Analyze graph b

Graph b shows a horizontal line for velocity. Slope of the $v - t$ graph is zero. So, acceleration $a = 0$.

Step4: Analyze graph c

Graph c shows a linearly decreasing velocity. Slope of $v - t$ graph is non - zero. So, acceleration is non - zero.

Step5: Analyze graph d

Graph d shows a linearly increasing velocity. Slope of $v - t$ graph is non - zero. So, acceleration is non - zero.

Answer:

B) only graph b