5. what is the acceleration of a car that travels in a straight line at a constant speed? 6. describe a…

Explanation:

Step1: Recall acceleration definition

Acceleration is the rate of change of velocity. Velocity is a vector - it has both magnitude (speed) and direction.

Step2: Analyze question 5

If a car travels in a straight line at a constant speed, there is no change in speed and no change in direction (since it's straight - line motion). Using the formula $a=\frac{\Delta v}{\Delta t}$, where $\Delta v = 0$ (no change in velocity), so $a = 0$.

Step3: Analyze question 6

When an object moves in a circular path at a constant speed, the speed remains the same but the direction is constantly changing. Since velocity is a vector and direction is changing, there is a change in velocity. According to the acceleration formula $a=\frac{\Delta v}{\Delta t}$, when $\Delta v\neq0$, there is acceleration. For example, a car moving around a circular track at a steady speed is constantly accelerating towards the center of the circle (centripetal acceleration).

Answer:

5. The acceleration is 0.
6. A car moving in a circular path at a constant speed is accelerating because its direction is changing.