4.48. Compound Machine http://www.ck12.org
FIGURE 4.94
have a greater mechanical advantage than simple machines. That’s because the mechanical advantage of a compound
machine equals the product of the mechanical advantages of all its component simple machines. The greater the
number of simple machines it contains, the greater its mechanical advantage tends to be.
Q: Assume that the lever and the wheel and axle of a wheelbarrow each have a mechanical advantage of 2. What is
the mechanical advantage of the wheelbarrow?
A: The mechanical advantage of the wheelbarrow is the product of the mechanical advantage of the lever (2) and the
mechanical advantage of the wheel and axle (2). Therefore, the wheelbarrow has a mechanical advantage of 4.
Summary
- A compound machine is a machine that consists of more than one simple machine.
- Compound machines such as a wheelbarrow or corkscrew consist of just two simple machines. Big compound
machines such as cars consist of hundreds or thousands of simple machines. - Compared with simple machines, compound machines generally have lower efficiency but greater mechanical
advantage.