The "***" is my answer
4. How do simple machines make work easier?
a. they decrease the distance needed between a person and an object, allowing the person to apply more force and do more work
b. they reduce the amount of force needed to move an
object to do the same amount of work ***
c. they magnify the force being applied, thereby decreasing the work they can do with no extra energy exerted by the person using the machine
d. they increase the distance over which a force is needed, doing more work with less force
To find the correct answer, we need to understand what simple machines are and how they work.
Simple machines are basic mechanical devices that can help make work easier by changing the magnitude or direction of applied force. There are six types of simple machines: lever, pulley, wheel and axle, inclined plane, wedge, and screw.
Option a states that simple machines decrease the distance between a person and an object, allowing them to apply more force and do more work. While it is true that some simple machines can decrease the distance, this does not necessarily make work easier. In fact, it may require more force to be exerted over a shorter distance.
Option c states that simple machines magnify the force being applied, decreasing the work they can do with no extra energy exerted by the person using the machine. This is incorrect because simple machines do not magnify force; they only change its direction or magnitude.
Option d states that simple machines increase the distance over which a force is needed, doing more work with less force. This is also incorrect as simple machines may increase the distance traveled, but it does not necessarily make work easier. In fact, it may require more force to be exerted over a longer distance.
Option b states that simple machines reduce the amount of force needed to move an object to do the same amount of work. This is the correct answer. Simple machines can reduce the force needed to move an object by using mechanical advantage, which is the ratio of output force to input force. By increasing the mechanical advantage of a simple machine, less force is required to accomplish the same amount of work.
Therefore, the correct answer is b. Simple machines reduce the amount of force needed to move an object to do the same amount of work.