Question

Answer the following questions for projectile motion on level ground assuming negligible air resistance, with the initial angle being neither 0�� nor 90��: (b) Is the vector v����� ever parallel or antiparallel to the vector a�����? (c) Is the vector v ever perpendicular to the vector a? If so, where is this located?

Answer 1

In projectile motion, the acceleration due to gravity is always directed downwards and never zero. The velocity vector becomes perpendicular to the acceleration vector at the peak of the trajectory. Except at initial launch and final impact for horizontal launch, the velocity vector is never parallel or antiparallel to the acceleration vector.

Step-by-step explanation:

When considering projectile motion on level ground with negligible air resistance and an initial launch angle that is neither 0° nor 90°:

• The acceleration is never zero because gravity is constantly acting downwards.
• The acceleration vector, “a”, is always directed downwards, and it is never parallel or antiparallel to the velocity vector, “v”, except at the very beginning and the end of the trajectory if the projectile is launched horizontally.
• The velocity vector “v” is perpendicular to the acceleration vector “a” at the peak of the trajectory where the vertical component of the velocity is zero.

The acceleration is in the opposite direction of the vertical component of the velocity vector for the entire duration of the projectile's flight, except at the peak where they are perpendicular.