Question

Suppose that a NASCAR race car is moving to the right with a constant velocity of +82 m/s. What is the average acceleration of the car? (b) Twelve seconds later, the car is halfway around the track and traveling in the opposite direction with the same speed. What is the average acceleration of the car?

I understand (a) but I don't understand how to solve for (b) can someone please help me?

Answer 1

I don't understand any of it :/

Answer 2

For part a constant velocity means there is 0 acceleration.

For the b start by realizing that acceleration is defined as the rate of change in velocity with respect to the change in time. Mathematically it's defined as:
\[a=\frac{V_{final}-V_{initial}}{\Delta time}\]
Plug in the values you were given and you end up with:
\[a=\frac{-82m/s-82m/s}{12s}=-13.67m/s^2\]

If that doesn't make sense please let me know what part is confusing you and I can try to explain it in more detail.