Final answer:
Machines can make work easier by altering the direction of movement or by reducing the input force needed, while increasing distance covered. Mechanical advantage describes a machine's capability to amplify force.
Step-by-step explanation:
A machine can make work easier by changing or lowering the direction an object moves or the amount of force required to do the work. Simple machines, such as levers, gears, pulleys, wedges, and screws, can modify the force applied to an object, often allowing a greater distance to be covered.
While a simple machine does not decrease the total amount of work performed, it offers a trade-off: reduce the amount of input force at the expense of increasing the distance over which the force is applied. The concept of mechanical advantage (MA) is key to understanding simple machines. MA is the ratio of output to input force magnitudes, indicating how much the machine amplifies the force applied.
The usefulness of simple machines lies in their ability to make tasks more manageable by altering how and over what distance a force is applied, rather than altering the amount of work overall. This is due to the conservation of energy, as no machine can output more work than the energy input into it.