What is the difference between thrust and drag in a moving car?

• A. Drag propels the car forward; thrust resists motion due to air.
• B. Thrust propels the car forward; drag resists motion due to air.
• C. Thrust and drag are unrelated to motion.
• D. Thrust and drag both act in random directions.

Answer: (B)

Thrust is the forward force produced by the engine as it pushes the car through the wheels, while drag is the air resistance that acts opposite to the car’s motion. In a moving car, thrust pushes it forward and drag pushes backward, opposing the motion. The car’s acceleration or top speed depends on how these forward and backward forces balance (along with other resistances like rolling friction). So the correct idea is that thrust propels the car forward and drag resists motion due to air. The other statements either flip the directions or say the forces don’t affect motion, which isn’t accurate.