Question

multiple choice 1 point
a baseball was thrown with an initial velocity of 14 m/s at an angle above the horizontal. it remained in the air for 2 s.
which of the following quantities was constant while the baseball was in the air?
acceleration
velocity
position
displacement

Explanation:

Step1: Analyze forces on baseball

When a baseball is in - air, the only force acting on it (neglecting air - resistance) is the gravitational force.

Step2: Recall Newton's second law

According to Newton's second law $F = ma$. The gravitational force $F = mg$ where $m$ is the mass of the baseball and $g$ is the acceleration due to gravity ($g\approx9.8m/s^{2}$ near the Earth's surface). So the acceleration of the baseball is constant and equal to $g$ (downward).

Step3: Analyze other quantities

The velocity of the baseball is changing because there is an acceleration acting on it. The position and displacement are also changing as the baseball moves through the air.

Answer:

Acceleration