Which of the following is a device that measures linear force by evaluating torque?

The device that measures linear force by evaluating torque is indeed the dynamometer. A dynamometer is specifically designed to measure the torque or force produced by an engine or any rotating object. It calculates the force by evaluating the twisting effect (torque) around an axis, which is directly related to the linear force being measured.

In practical terms, when you're trying to determine how much force a machine can exert or how much work it can do, a dynamometer provides a straightforward way to convert the rotational force (torque) into measurable units of linear force, allowing for precise assessments of mechanical performance. This capability makes it an essential tool in both engineering and testing environments, especially in applications where engines or motors are involved.

The other options, while they are measuring devices in their respective contexts, are not relevant for measuring linear force via torque. A scale measures weight based on gravitational force, a hydrometer assesses the density of liquids based on buoyancy, and a manometer measures pressure based on the height of a liquid column. None of these devices involve the evaluation of torque to derive linear force, making the dynamometer the correct choice in this scenario.