Please help, just one question. Explain.
What is the average acceleration of a jet ski that goes from rest to 10 m/s west in 4 s? Take the direction west to be positive, and east to be negative. Explain.
A. 2.5 m/s^2
B. -2.5 m/s^2
C. 0.4 m/s^2
D. -0.4 m/s^2