Which of these is a simple machine?
A.
Bicycle
B.
Clock
C.
Pulley
D.
Toaster
C. Pulley
The simple machine from the given options is C. Pulley.
To determine which of these options is a simple machine, let's start by understanding what a simple machine is. A simple machine is a mechanical device that helps perform work with the application of force. It typically operates on the principles of basic physics, such as leverage, inclined planes, wheels and axles, screws, wedges, or pulleys.
Now, let's analyze the options:
A. Bicycle: A bicycle is not considered a simple machine itself but rather a complex machine. It consists of several simple machines, such as the wheel and axle, gears, and the lever system of pedals and cranks.
B. Clock: Similar to a bicycle, a clock is not a simple machine. It is composed of various gears, levers, and wheels working together to measure time but is not considered a single simple machine.
C. Pulley: A pulley is indeed a simple machine. It consists of a grooved wheel with a rope or chain running along it. The purpose of a pulley is to lift or move heavy loads by reducing the amount of force required.
D. Toaster: A toaster is not considered a simple machine. It involves multiple components, such as heating elements, a timer, and a control system, rather than operating on basic mechanical principles.
Based on the analysis, the correct answer is C. Pulley, as it is the only option that represents a simple machine according to its definition.