Final answer:
The mass of material expelled from a racer's tailpipe will be roughly the same as the mass of fuel burned, which is 150 grams, following the conservation of mass in physics.
Step-by-step explanation:
The amount of material expelled from a racer's tailpipe can be explained by the conservation of mass, a fundamental concept in physics. When the racer puts 150 grams of fuel into the vehicle and burns it entirely, assuming complete combustion, the mass of the exhaust gases expelled will be roughly equivalent to the mass of the fuel burned, which is 150 grams. However, the exact composition and state of these exhaust gases will depend on the engine's efficiency and the types of fuel used.