Question bank: Simple and Thermal Machines

One of the main characteristics of the lever is that it allows the multiplication of effort, that is, increasing the ability to perform work with less physical effort. This occurs due to the mechanical properties of the lever, such as the balance of moments and the action-reaction principle. When we apply a force on the lever to perform work, what will be the result?

A thermal machine operates with a hot reservoir at a temperature of 500°C and a cold reservoir at 100°C. The machine receives 2000 J of heat from the hot reservoir and, operating according to the Carnot cycle, performs a work W. Considering that the efficiency of a Carnot thermal machine is given by η = 1 - (Tc/Th), where η is the efficiency, Tc is the temperature of the cold reservoir, and Th is the temperature of the hot reservoir, calculate the work done by the thermal machine. Then, relate the concept of efficiency of a thermal machine to the concept of energy efficiency, explaining how the machine's efficiency is related to the amount of heat wasted during the process. For the calculation of work, use the formula W = η * Qh, where W is the work done, η is the efficiency of the Carnot machine, and Qh is the heat received from the hot reservoir.

Springs are mechanical devices that have the ability to store energy. When compressed or stretched, they maintain a constant force, which is called elastic force. This force is responsible for performing mechanical work and can be found in various objects and equipment, such as machines, engines, clocks, and even toys. Which of the following items does not have a spring inside?

Simple machines are tools created to perform mechanical tasks in an easier, faster, and more efficient way. They are considered the basis of mechanics because they help facilitate human work. What are the main elements that make up a simple machine?

Thermal machines are devices that convert thermal energy into mechanical energy, and this is possible thanks to the laws of thermodynamics, which establish the principle of conservation of energy. These devices can be used to generate motive force in various equipment, such as marine engines and electric generators used in hydroelectric plants. Which of these equipment does not depend on the operation of thermal machines?