In the Enem Nature Science exam, the questions are divided between Chemistry, Biology and Physics subjects. And it is the main subject charged in this last subject that we are going to treat today: the mechanics. According to Professor Anderson Rodrigues, known as Bill, from the Student Workshop course, mechanics has been the flagship of the discipline in the exam for at least two years.
“The student must give much importance to the mechanics in the hour of the studies, because, in Physics, it is still the subject that most falls in the vestibular”, says. Bill recalls that the best way to learn the subject is by solving previous evidence exercises to understand the patterns of issues in which the theme appears and is charged.
He underscores the thematic is divided into some topics that appear recurrently in the examination: kinematics, mechanical energy and work, dynamics, momentum and momentum. See how and what to study in each of them.
According to the professor, in the kinematics, most of the questions bring the Uniformly Varied Movement (MUV). Exercises that charge MUV are usually associated with statements of free fall or vertical, horizontal or oblique throws.
In order to do well in the test, Bill emphasizes that it is important to know the MUV graphs and the formulas, such as the Torricelli equation (v² = v0² + 2ΔΔS). The teacher further emphasizes that the problems listed by the Enem are contextualized. “They are uniformly varied motion issues, but associated with everyday situations. A model that has appeared, for example, is asking the candidate to calculate data such as speed and acceleration of Superman, “he explains.
Work and mechanical energy
Conservative systems, where the mechanical energy of the beginning is equal to that of the end, are often charged by Enem. The teacher recalls that the test also brings questions of the kinetic energy theorem (τ AB = E cB – E cA = ΔE c ) and mechanical power.
“Enem has already brought a problem about power related to the Itaipu Hydroelectric Power Plant working with the idea of waterfall. It’s very much the face of the test, a kind of question that can even appear in other vestibules, “explains Bill.
The third area of mechanics that most appears in the examination is dynamics, with Newton’s Laws. It comes in exercises that ask for elements like friction and components of the resultant, with centripetal force and centripetal acceleration. According to the professor, most of the questions are theoretical and graphical.
“The evidence may ask, for example, for the applicant to associate the comfortable acceleration for passengers of a curved-sized train, which makes a curved path. This is completely connected to the centripetal acceleration, “he says.
Impulse and amount of movement
The momentum and momentum appear in questions dealing with collisions and by the impulse Theorem (I = ΔQ). One of the ways in which the subject was charged by the examination was in a problem that reported a collision between carts on an air path, in a laboratory experiment, the professor says.
The teacher also emphasizes that it is important to study the subject thinking about interdisciplinary issues, since many of the questions in the test bring statements related to the dynamics and work with Newton’s second Law ( ). It is also common to see problems that work with conservation of momentum in conservative systems, or relation of momentum and momentum with work and energy.
According to the professor, interdisciplinarity is a resource adopted by the exam to not only address simpler content and also to condense the evaluation of several learning in a single test of Nature Sciences. “The current Enem even has issues of a single theme, but since the model brings few questions of physics, there is a high incidence of questions that mix issues,” he explains.
Within the mechanics, other subjects that are not very frequent in the Enem, but that always appear in the other vestibular ones are the static, the hydrostatic and the gravitation. The teacher also emphasizes that the other tests also certainly bring the main points of the exam, but in a different way. “The level of collection is different, the issues are more direct and less contextualized,” he explains.
Sample questions template:
60 – letter C
64 – letter B
83 – letter C
67 – letter A