By the Pythagorean theorem, the magnitude of the total velocity, v, is
50 m/s.
- E Since the acceleration of the projectile is always downward (because it’s
gravitational acceleration), the vertical speed decreases as the projectile
rises and increases as the projectile falls. Choice (A) is false because
gravity always points down. Choice (B) is false because the projectile still
has its horizontal velocity at the top of the trajectory. Choice (C) is false
because the vertical component of the velocity changes, even if the horizontal
component does not, so the total speed changes. Choice (D) is false because
the horizontal component is constant throughout the motion.
