Question

a projectile can ____. include all that apply.
a. have an overall constant speed
b. experience a balance of forces
c. be moving upwards
d. be on a surface
e. encounter air resistance
f. be moving downwards

Explanation:

• A projectile is an object moving through the air, only acted on by gravity (and optionally air resistance).
• a: Projectiles accelerate downward, so speed changes (vertical component changes), so this is false.
• b: Gravity acts on projectiles, so forces are unbalanced, this is false.
• c: Projectiles can move upward (e.g., a thrown ball rising), this is true.
• d: Projectiles are in air, not on a surface, this is false.
• e: Real-world projectiles can encounter air resistance, this is true.
• f: Projectiles move downward as gravity pulls them (e.g., a falling ball), this is true.

Answer:

c. be moving upwards
e. encounter air resistance
f. be moving downwards