Question

Answer the following questions for projectile motion on level ground assuming negligible air resistance (the initial angle being neither 0º nor 90º): (a) Is the velocity ever zero? (b) When is the velocity a minimum? A maximum? (c) Can the velocity ever be the same as the initial velocity at a time other than at t=0? (d) Can the speed ever be the same as the initial speed at a time other than at t=0?

a) (a) No. (b) Minimum at the top; maximum at launch. (c) Yes. (d) Yes.

b) (a) Yes. (b) Minimum at launch; maximum at the top. (c) No. (d) No.

c) (a) Yes. (b) Minimum at the top; maximum at launch. (c) Yes. (d) Yes.

d) (a) No. (b) Minimum at launch; maximum at the top. (c) No. (d) No.

Answer 1

Velocity is never zero for a projectile in motion on level ground. Velocity is at a minimum at the trajectory's peak, and at maximum at launch. Although velocity direction changes, the speed can equal the initial speed upon landing at the launch elevation.

Step-by-step explanation:

For projectile motion on level ground with negligible air resistance and an initial launch angle between 0° and 90°, the answers to the questions are: (a) No, the velocity is never zero because the projectile is always moving until it hits the ground. (b) The velocity is at a minimum at the peak of the trajectory, where the vertical component is zero but horizontal component remains constant. The velocity is at a maximum at launch due to the full initial kinetic energy.

(c) The velocity cannot be the same as the initial velocity at any other point in time because its direction changes during flight. (d) Yes, the speed - the magnitude of the velocity - can be the same as the initial speed when the projectile lands, assuming it lands at the same elevation from which it was launched.