Question

A baseball player hits a ball that soars high into the air. After the ball has left the bat, and while it is traveling upward (at point P in Fig. 3–31), what is the direction of acceleration? Ignore the air resistance.

FIGURE 3-31 Misconceptual question 5

Short answer

The direction of the acceleration is downward.

Step-by-step solution

Step 1. Trajectory of a projectile

When an object is launched at an angle, it follows a curved path, which is called the trajectory under the action of acceleration due to gravity. At the center of the path at the maximum height, the acceleration due to gravity is g. The particle's velocity is always tangential, and at maximum height, the vertical component of the velocity is zero.

Step 2. Meaning of air resistance

The air resistance opposes the relative motion of the object in the air. It depends on the mass and velocity of the object. After ignoring the air resistance, the ball would travel on its own. The situation in option (a) results in that ball not stopping and continuing to accelerate. On the other hand, according to option (c), the ball travels towards the batsman, and it cannot be true. Therefore, options (a) and (c) are incorrect.

Thus, the correct option is (b).