If a machine changes only the direction of a force, it means that it has the mechanical advantage 1.
Answer: Option D
Step-by-step explanation:
When a machine turns a small amount of input force into a large amount of output force, it is known to have a mechanical advantage. This mechanical advantage may vary for different machines and mechanical devices.
For example, machines that produces larger output force as compared to the input force, they are said to have a mechanical advantage greater than one. For those that produces significantly smaller amount of output force as compared to the input force, the advantage is less than 1.
And, there come some of the mechanical devices such as pulley, that don’t change the magnitude of force only the direction. For such machines, the mechanical advantage remains one. The standard formula to estimate the mechanical advantage is,
Actual Mechanical Advantage = Output force / Input force