Which statements are true?
A.
Simple machines have no moving parts.
B.
When we use a simple machine, we do less work.
C.
A motor scooter is a simple machine.
D.
A screwdriver is a simple machine.
E.
A screw is a simple machine.
B. When we use a simple machine, we do less work.
D. A screwdriver is a simple machine.
E. A screw is a simple machine.
The true statements are B and D.
B. When we use a simple machine, we do less work. This is true because simple machines are designed to make work easier by reducing the amount of force or effort required to perform a task.
D. A screwdriver is a simple machine. This is true. A screwdriver is a type of lever, which is one of the six simple machines. It helps to turn or tighten screws by applying torque and rotational force.
To determine which statements are true, we can analyze each statement individually.
A. Simple machines have no moving parts.
To verify this statement, we need to understand what a simple machine is. Simple machines are basic mechanical devices that make work easier. They can be found in many everyday objects, such as levers, pulleys, and ramps. While some simple machines have moving parts, not all of them do. Examples of simple machines that do not have moving parts include a wedge or an inclined plane. Therefore, statement A is not entirely correct.
B. When we use a simple machine, we do less work.
This statement is generally true. Simple machines are designed to multiply or change the direction of the effort force applied, making it easier to do work. By using a simple machine, we can reduce the amount of force needed or the distance over which the force must be applied. Thus, statement B is true.
C. A motor scooter is a simple machine.
A motor scooter is a mode of transportation that combines several complex systems, such as an internal combustion engine, transmission, and various mechanical components. It cannot be considered a simple machine because it involves multiple interacting parts and systems. Therefore, statement C is false.
D. A screwdriver is a simple machine.
A screwdriver can be classified as a simple machine. Specifically, it is a modified lever since it amplifies rotational force to turn screws, which are inclined planes wrapped around a cylinder. So, statement D is true.
E. A screw is a simple machine.
A screw is indeed classified as a simple machine. It is essentially an inclined plane wrapped around a cylindrical post. The spiral threads of the screw allow it to convert rotational motion into linear motion, making it useful for a variety of applications. Therefore, statement E is true.
In summary, the true statements are B (When we use a simple machine, we do less work), D (A screwdriver is a simple machine), and E (A screw is a simple machine).