What is the definition of input force?

The definition of input force refers specifically to the effort exerted by a person or an external source on a machine. This is the force that initiates the operation of the machine and is essential for understanding how machines work. Input force is crucial because it influences how much work the machine can do in terms of output. The term "effort" is commonly used in physics to describe this input force, highlighting the active role the user plays in the functioning of a machine.

The other options describe various aspects of machines but do not correctly define input force. For instance, the force attributed to gravity acting on a machine pertains to the weight of the machine or its components, not the effort applied. The total force generated by the machine relates to its mechanical advantage and output force, while the force that the machine exerts on an object is indicative of the output force or load, rather than the input force. Understanding these distinctions is vital for grappling with concepts of mechanics and how machines utilize input force to perform work.