Which of the following statements are true about an object in two-dimensional projectile motion if we neglect air? (There could be more than one correct choice.)
A)The speed of the object is constant but its velocity is not constant.
B)The acceleration of the object is +g when the object is rising and -g when it is falling.
C)The acceleration of the object is zero at its highest point.
D)The speed of the object is zero at its highest point.
E)The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward.

Question

Quizplus · Accepted Answer

The acceleration of an object in two-dimensional projectile motion (neglecting air resistance) is due to gravity, which acts downward. This means the horizontal acceleration is always zero (since gravity does not pull the object sideways), and the vertical acceleration is a non-zero constant downward, represented by $g$ (approximately $9.8 \, \text{m/s}^2$ on the surface of the Earth). This is true throughout the entire flight of the projectile, regardless of its position.

Which of the Following Statements Are True About an Object