Is the Car's Motion and Acceleration Negative in Strobe Photography Analysis?

[williamx11373]

a strobe photograph of a car moving along a straight road shows the interval between each successive image to be diminishing. If the direction of motion of the car is taken as positive, which of the following are negative?

a. the speed of the car
b. the average velocity of the car
c. the average acceleration of the car
d. all of the above


im guessing its D. because velocity and acceleration is somewhat related.

 

[mgb_phys]

Time to do a bit more thinking.
Try drawing a diagram.
On a ruler suppose the car starts at 0, then it's at 6 (cm or inch), then 10, then 12 in equal time intervals.
Whats happening to the speed?
What do we call a change in speed