What instrument is likely used to measure frictional forces?

The instrument specifically designed to measure frictional forces is a friction tester. This tool directly quantifies the resistance encountered when two surfaces slide against each other, effectively measuring the coefficient of friction. Friction testers can provide critical data in applications ranging from material science to automotive engineering, as understanding friction is essential for optimizing performance, safety, and efficiency in various systems.

Other instruments mentioned have distinct purposes. A caliper is primarily used for measuring dimensions and distances with high precision, making it unsuitable for assessing frictional forces. A manometer measures pressure differences, typically in fluids, and does not relate to frictional measurements. An accelerometer measures acceleration forces and is used primarily in dynamics, making it irrelevant for direct friction measurement. Thus, the friction tester is the correct choice as it is specifically designed for the task at hand.