A projectile is fired at an angle of elevation of 45°.Neglecting air resistance,what are possible angles in flight between the acceleration vector and the velocity vector?

A) 160° and 40°
B) 20° and 70°
C) 90° and 45°
D) none of the above
E) 10° and 45°

Question

A projectile is fired at an angle of elevation of 45°.Neglecting air resistance,what are possible angles in flight between the acceleration vector and the velocity vector?
​
A) 160° and 40°
B) 20° and 70°
C) 90° and 45°
D) none of the above
E) ​10° and 45°

Quizplus · Accepted Answer

When a projectile is fired at an angle of 45 degrees, the velocity vector is split equally into horizontal and vertical components. As air resistance is neglected, the acceleration vector is equal to the gravitational force acting downwards. During the projectile's motion, the direction of the velocity vector changes continuously, while the acceleration vector remains constant. At the highest point of the projectile's path, the velocity vector is perpendicular to the acceleration vector. Thus, the only possible angles between the acceleration and velocity vectors are 90 degrees and 45 degrees. Therefore, the correct choice is (C) 90° and 45°.

A Projectile Is Fired at an Angle of Elevation of 45°.Neglecting