Water Wheels — Undershot Type and Driving Mechanism Undershot water wheels are those in which the wheel is driven primarily by which action of the water?

Introduction:
Traditional water wheels are categorized as overshot, breastshot, and undershot depending on where water strikes the wheel and how energy is transferred. Understanding the dominant driving mechanism clarifies where each type is suitable.

Given Data / Assumptions:

• Low head, high flow rivers suitable for undershot wheels.
• Undershot: water meets paddles near the bottom of the wheel.

Concept / Approach:
Undershot wheels are impulse devices. Flowing water strikes the paddles at low head, imparting momentum change to produce torque. Overshot relies mainly on weight (potential energy), while breastshot is mixed (weight + impulse).

Step-by-Step Solution:
Identify strike position: near bottom indicates undershot.Dominant energy transfer: impulse from water velocity acting on paddles.Therefore, wheel runs by the impulse of water.

Verification / Alternative check:
Classic classifications: undershot (impulse), overshot (weight), breastshot (combination) are widely documented in hydraulic machinery texts.

Why Other Options Are Wrong:

• Entirely by weight: describes overshot wheels.
• Partly weight and partly impulse: describes breastshot wheels.
• None of the above: incorrect since one option fits precisely.

Common Pitfalls:
Confusing geographical installation style with energy mechanism; the key is where and how water meets the wheel.

Final Answer:
the wheel runs entirely by the impulse of water