Attempting to stop on a slippery road, a car initially moving at 80 km/h skids at 30° to its initial motion, stopping in 3.9 s. Determine the average acceleration in m/s2 in coordinates with the x-axis in the direction of the original motion and the y- axis toward the side to which the car skids.

Answer 1

initial speed = 80,000 m/3600 s = 22.2 m/s

initial x speed = 22.2 cos 30 = 19.25 m/s
final x speed = 0
ax = -19.25/3.9

initial y speed = 22.2 sin 30 = 11.1 m/s
final y speed = 0
ay = -11.1/3.9