Question

1. ______________ make a very compact way to form compound machines.
2. often in designing machinery it is helpful to be able to calculate __________ rather than _____________.
3. what can be used to calculate the speed? ___________________________________________
4. a series of gears can give several different mechanical advantages and even __________________ motion.

Explanation:

These questions seem to be related to mechanical engineering (a subfield of Engineering under Natural Science) and are about machine design, gears, and mechanical calculations. Here are the answers based on mechanical engineering concepts:

1.

Gears are used to form compound machines in a compact way as they can transmit motion and force efficiently.

In machinery design, calculating mechanical advantage (a measure of the force amplification) is more helpful than just calculating force directly as it gives insight into the machine's efficiency in multiplying force.

To calculate speed (especially in rotational or linear motion related to machines), formulas involving distance (or displacement) and time, or for rotational speed, the gear ratio (number of teeth or rotational frequency) can be used. For example, the formula \( v=\frac{d}{t} \) (linear speed) or for gear systems, the speed ratio (inverse of gear ratio for rotational speed) can be used. Also, tachometers (devices) can measure speed directly.

Answer:

Gears

2.