Object P moves in a straight line with increasing speed, so it has an acceleration in the direction of motion. Object Q moves at constant speed in a circle, so it only experiences centripetal acceleration perpendicular to motion. Object R moves along a curved path with increasing speed, so it experiences Euler and Coriolis forces providing an acceleration in the direction of motion. Therefore, the objects with acceleration components in the direction of motion are objects P and R.

1. The following information relates to the motion of three objects P, Q and R. I. object P moves in
a straight line with increasing speed Il object Q moves in a circle with constant speed II. object R
moves along a curved path with increasing speed in which of the three cases has the object an
acceleration component in the direction of motion? Select one: a. I only b. I and II only c. I and
III only d. I and III only e. III only
Solution
For opject P, the acceleration is in the direction of motion
Since object Q is moving at constant speed in a circle, it has only centripetal acceleration. The
centripetal acceleration is only along the radial direction (perpendicular to the direction of
motion)
For object R, the Euler and coriolis force is along direction of the motion.
Hence the answer is object P and object R has an acceleration component in the direction of
motion.
d. I and III only