Which statement correctly describes a difference between V-belt and timing belt drives?

• A. V-belts can slip under load; timing belts provide positive engagement and better alignment.
• B. V-belts are quieter with less maintenance than timing belts.
• C. Timing belts slip under load more than V-belts.
• D. V-belts do not slip under load and require no maintenance.

Answer: (A)

The difference being tested is how motion is transmitted from the pulley to the belt. V-belts rely on friction inside a V-groove to grip the pulley. Under heavy load or high heat, that friction can fail to hold, causing the belt to slip and the driven speed to drop or pulsate. Timing belts, on the other hand, have teeth that mesh with matching grooves on the pulleys, creating positive engagement. This interlocking keeps the belt from slipping and helps keep the pulleys in sync, which also improves alignment.

So the statement that V-belts can slip under load and timing belts provide positive engagement and better alignment captures the fundamental difference. The other claims contradict how friction-based belts vs toothed, positively engaged belts transfer motion.