What substance reduces friction and wear, dissipates heat, and protects metal surfaces from rusting?

• A. Adhesives
• B. Lubricants
• C. Coolants
• D. Brake Fluid

Answer: (B)

Lubricants form a thin film between moving metal surfaces, which cuts down on friction and wear and lets parts move smoothly. They also carry heat away from contact areas, helping to dissipate it and prevent overheating. In addition, lubricants contain additives that resist corrosion and moisture, forming a protective barrier that helps prevent rust on metal surfaces.

Adhesives bond surfaces together, which would increase resistance to motion rather than reduce it. Coolants mainly remove heat from the engine and aren’t intended to provide ongoing lubrication or rust protection for moving parts. Brake fluid is used to transmit hydraulic pressure in the braking system, not to lubricate engine components or guard against wear and rust.