# FISICA GENERALE I A - LModule ESERCITAZIONI

Academic Year 2023/2024 - Teacher: GIOVANNA FERRARA

## Course Structure

The teaching activity consists of exercises (for a total of 2 ECTS, corresponding to 30 hours), accompanied by tutoring activities(*). The exercises provide for the resolution, both guided and autonomous, of tasks and exercises. Where possible, innovative teaching and learning strategies are

used. During each lesson, moreover, space is left to students for questions, curiosities and comments, in order to maximize teacher-student interaction.

(*) If specialist tutors are available for the course during the academic year.

## Required Prerequisites

It is fundamental for the student to have mastery of the subjects of elementary mathematics (algebra, geometry, trigonometry, analytical geometry) and knowledge of those of mathematical analysis (differential and integral calculus). In fact, for the presentation of the physical concepts included in the

course content, the following mathematical tools are used: equations and systems of 1st and 2nd degree equations, trigonometric functions and their properties, exponential functions and their properties, logarithmic functions and their properties, equations of loci in the plane and in space, derivatives and integrals of functions of one variable, constant coefficient linear differential equations. For the self-paced learning, and/or consolidation, of the required preliminary knowledge, the mathematics and basic calculus courses available on e-learning platforms such as, for example, Federica Web Learning and Coursera for Campus, to which students of the University have access, may be useful.

## Attendance of Lessons

Normally mandatory (as stated in the Didactic Regulation of the course)

## Detailed Course Content

MECHANICS

Exercises on kinematics. Speed, velocity, acceleration and time dependence of motion. Straight and uniformly accelerated rectilinear motion. Vertical motion. Simple harmonic motion. Rectilinear motion exponentially damped. Motion in a plane: velocity and acceleration. Circular motion. Parabolic motion.

Exercises on dynamics of the material point. Principle of inertia and the concept of force. Second and third Newton's law. mpulse and momentum. Resulting force: binding reactions and equilibrium. Examples of forces: weight force, sliding friction force, viscous friction force, centripetal force, elastic force. Inclined plane. Simple pendulum. Wire tension. Reference systems. Relative speed and acceleration. Inertial reference systems.

Exercises on work and energy. Work, power and kinetic energy. The theorem of the kinetic energy. Examples of works done by forces. Conservative forces and potential energy. Non-conservative forces. Principle of conservation of mechanical energy. Relationship between force and potential energy. Angular momentum. Torque. Central forces.

Exercises on dynamics of systems of material points. Systems of points. Internal and external forces. Center of mass and its properties. Principle of conservation of the momentum. Principle of conservation of the angular momentum. The König theorems. Theorem of the kinetic energy. Collisions.

Exercises on dynamics of the rigid body. Motion of a rigid body and basic motion equations. Continuous bodies, density and the position of the center of mass. Rigid rotations around an axis in an inertial reference system. Rotational energy and work. Moment of inertia. Huygens-Steiner's theorem. Compound pendulum. Pure rolling motion. Energy conservation in the motion of a rigid body.

Exercises on dynamics of fluids. Fluids properties and pressure. Pascal’s Principle. Stevin’s law. Archimede’s law. Motion of a fluid and Bernoulli’s theorem.

Exercises on oscillations and waves. Properties of the differntial equation of the harmonic oscillator. Simple harmonic oscillator: motion equation and its solution. Motion of a mass connected to a spring. Energy of a simple harmonic oscillator. Damped and forced harmonic oscillators. Characteristics of a wave: amplitude, period, frequency, wavelenght, intensity. Wavefunction. Waves on a string. Waves on gases.

Exercises on gravitation. Kepler's laws. The Universal Gravitation Law. Gravitational field and gravitational potential energy. Escape velocity,

THERMODYNAMICS

Exercises on the first principle of thermodynamics. Thermodynamic systems and states. Thermodynamic equilibrium and the Principle of Thermal Equilibrium. Temperature and thermometers. Equivalence of work and heat. First Principle of Thermodynamics. Internal energy. Thermodynamic transformations. Work and heat. Calorimetry. Phase transitions. Heat transmission.

Exercises on ideal gases. Laws of the ideal gas. Equation of state of the ideal gas. Transformations of a gas. Work. Specific heat and internal energy of the ideal gas. Analytical study of some transformations. Ciclic transformations. The Carnot cycle. Kinetic theory of gases. Equipartition of energy.

Exercises on the second principle of thermodynamics. Reversibility and irreversibility. Carnot's theorem. Clausius theorem. Entropy state function. The principle of increasing entropy of the universe. Entropy variations' calculations. Entropy of the ideal gas.

Exercises on thermodynamics potentials. Gibbs free energy. Helmholtz free energy. Henthalpy. Excercises on real gases. Transformations of a real gas described by the Van der Waals equation of state: work calculations, internal energy variation, heat, entropy variation for some transformations.

## Textbook Information

1) P. Mazzoldi, A. Saggion, C. Voci, Problemi di Fisica Generale-Meccanica, Termodinamica (Edizioni Libreria Cortina Padova 1996): Esercizi

2) M. Fazio, Problemi di Fisica (Springer, 2008)

## Course Planning

SubjectsText References
1 Exercises on kinematics (2 hours)  Textbook 1-Chapter 1; Textbook 2-Chapter 2
2 Exercises on dynamics of the material point (3 hours)  Textbook 1-Chapter 2; Textbook 1-Chapter 3; Textbook 2- Chapter 3; Textbook 2-Chapter 6
3 Exercises on work and energy (4 hours)  Textbook 1-Chapter 2; Textbook 2-Chapter 4
4 Exercises on dynamics of systems of material points (2 hours)  Textbook 1-Chapter 5; Textbook 2-Chapter 5
5 Exercises on gravitation (2 hours)  Textbook 1-Chapter 7; Textbook 2- Chapter 9
6 Exercises on dynamics of the rigid body (4 hours)  Textbook 1-Chapter 6; Textbook 2-Chapter 7
7 Exercises on dynamics of fluids (2 hours)  Textbook 1-Chapter 8; Textbook 2-Chapter 8
8 Exercises on oscillations and waves (2 hours)  Textbook 1-Chapter 4; Textbook 2-Chapter 15
9 Exercises on the first principle of thermodynamics (2 hours)  Textbook 1-Chapter 9; Textbook 1-Chapter 10; Textbook 2- Chapter 10; Textbook 2-Chapter 12
10 Exercises on ideal gases (2 hours)  Textbook 1-Chapter 9; Textbook 1-Chapter 10; Textbook 2- Chapter-11
11 Exercises on the second principle of thermodynamics (3 hours)  Textbook 1-Chapter 10; Textbook 2-Chapter 13
12 Exercises on thermodynamics potentials (1 hour)  Textbook 2-Chapter 14
13 Excercises on real gases (1 hour)  Textbook 2-Chapter 14

## Learning Assessment

### Learning Assessment Procedures

The exam consists of a written test and an oral interview. The written test consists of 3 (or 4) problems to be solved in a maximum time of 2 hours. To know the type of problems proposed, consult the website http://nanostar.jimdo.com/.
The evaluation of the written test will take into account the problem solving approach, the

correctness of the numerical calculations and significant values, the arguments supporting the procedure followed. The minimum mark for admission to the oral exam is 18/30.
The evaluation of the oral interview will take into account the student's ability to use orders of magnitude in the analysis of a phenomenon, the ability to critically evaluate similarities and differences between physical systems, the level of depth of the contents exposed and its properties of language and of exposure.

The written test has limited validity, it is necessary to complete the exam by passing the oral exam in the same calendar year as the written test. If the student does not complete the exam within the calendar year, he must repeat the written test.

Or for attending students:

the exam can be divided into two partial tests: one relating to mechanics
and gravitation (first partial test) and the second relating to thermodynamics, and fluid mechanics (second partial test). Passing both partial tests will determine the achievement of the exam. These partial tests are to be considered additional opportunities with respect to the exams and do not preclude participation in the ordinary exam sessions.
Both partial tests consist of a written test and an oral interview. The
written test consists of 3 problems to be solved in a maximum time of 2 hours (http://nanostar.jimdo.com/). The minimum mark for admission to the respective oral interviews is 15/30.

The first test takes place at the end of the first teaching period, in the February exam session. Students who pass the written test will have access to the oral interview which will determine admission to the second partial test.

The second partial test can be held in each of the ordinary sessions of the second and third session, according to the official calendar. The student who has passed the second written test will have access to the oral interview which will determine the final result of the exam.
The student who passes the second written test is allowed to take the
second oral interview even in a subsequent session, as long as it is within the calendar year of the written test.

The two partial written tests can be replaced by ongoing tests to be scheduled in agreement between the teacher and students.

Information fo students with disabilities and/or SLD

In order to guarantee equal opportunities and in compliance with the laws in force, interested students can ask for a personal interview in order to plan any compensatory and/or dispensatory

measures, according to the educational objectives and specific needs. It is also possible to contact the CInAP (Centro l'Integrazione Attiva e Partecipata - Servizi per le Disabilità e/o DSA)

contact-person of the Department, Prof. Catia Petta.

### Examples of frequently asked questions and / or exercises

The problems listed below are not an exhaustive list but are just a few examples:

1) Taking a coordinate system with horizontal x-axis and ascending vertical y-axis, let P be the point of coordinates xp = 0 m and yp = 120 m. A body of mass m = 2 kg is launched with initial horizontal velocity v0 = 15 m / s from point P. Determine:

a) the time of flight and the point of fall of the body on the ground;

b) the expression of the forces acting on the body, tangential and normal to the trajectory as a function of time and their value at instant t* corresponding to half of the flight time;

c) the expression, as a function of time, of the angular momentum and the moment of force with respect to the launch point P and their value at instant t*.

2) A mole of ideal monoatomic gas with initial volume V1 = 8 dm3 and temperature T1 = 350 K completes a reversible cycle consisting, in sequence, of: 1 → 2 isothermal expansion, 2 → 3 isochoric with pressure decrease, 3 → 4 isobaric compression, 4 → 1 adiabatic which brings the gas back to the initial conditions.

a) Determine the thermodynamic coordinates (pressure, volume, temperature) of states 2, 3, 4 in such a way that the entropy change of the gas from state 1 to state 2 is equal to 19 J / K and that the temperature of state 4 let T4 = 80 K;

b) Calculate the cycle yield.

3) A body with mass m1 = 1.00 kg, initially at rest, is dropped from a height h, with h = 12.0 m. At the same instant in which the body 1 starts its motion, a second body, with mass m2 = 2.00 kg, is launched from the ground with speed v20, along the same vertical. Given the conditions, the two bodies will collide; we indicate with tc and yc the instant and the altitude at which the collision occurs. Knowing that the collision between the two bodies is completely inelastic and that after the collision the body resulting from the union of the two (of mass m1 + m2) reaches a maximum height equal to h, determine:

a) the speed v20 with which the body 2 was launched;

b) the instant tc and the altitude yc at which the impact occurs;

c) the energy lost in the collision.

[Treat the bodies as point-like, neglect any friction and assume an instant impact]

4) A body, of mass m1 = 1000 kg, is launched in a radial direction from the earth's surface with an initial velocity v0 equal to 3/5 of its escape velocity, vfuga.

a) Determine the maximum distance rmax from the center of the Earth that reaches the body.

At the exact moment in which the body is at the distance rmax (the one calculated in the previous point), it is hit by a meteorite of mass m2 = 2m1. Knowing that the collision with the meteorite is completely inelastic and that the resulting body begins to rotate around the Earth on a circular orbit of radius rmax, determine:

b) the time it takes the body to make a complete circle around the Earth;

c) the velocity v2 that the meteorite had before the collision, specifying its direction;

d) the energy lost in the impact.

[In the calculations, neglect both the resistance of the atmosphere and the earth's rotation. For the ground mass and radius use the following values: M = 5.98 • 1024 kg, R = 6.37 • 106 m]

5) A parallelepiped-shaped body floats in a container partially filled with mercury (density 13.6 g / cm3), remaining immersed only for two thirds of its height. Subsequently, water is added (immiscible with mercury) in order to abundantly cover the emerging part of the parallelepiped. Calculate the x height of the

part immersed in mercury in the new conditions, knowing that the total height of the parallelepiped is h = 20 cm.

6) An ideal gas is contained in the volume VA = 40.00 dm3 at the pressure pA = 1.00 • 105 Pa and at the temperature TA = 300.0 K. With a reversible isothermal compression the gas reaches state B with volume VB = (1/3) VA ; during this transformation the gas performs a job LAB = −4.394 • 103 J. Then, through a reversible isochore it reaches state C at temperature TC = 600 K. Subsequently, in an irreversible adiabatic way, the gas is brought to state D with volume VD = VA and temperature TD> TA: in this expansion the gas does the job LCD = 5.894 • 103 J. Finally, with a reversible isochore the gas returns to the initial state A. Knowing that the cycle efficiency is η = 0.150, to determine:

a) the heat QAB, QBC and QDA;

b) if the gas is monoatomic or diatomic;

c) the value of TD;

d) the change in entropy DSCD.

7) To a solid state body of mass m = 2 kg and at the initial temperature T0 = 282.2 K, an amount

of heat Q1 = 15.5 kcal is transferred and, correspondingly, its temperature rises to the value

T1 = 317.2 K. Now that the body is at temperature T1, the quantity of heat Q2 = 7.9 kcal is

subtracted from it and, correspondingly, its temperature drops to the value T2 = 302.2 K. If, on

the other hand, a quantity of heat Q is transferred to the body at temperature T1 <Q2 it is

observed that its temperature remains constant at the T1 value.
Assuming that the specific heat c of the body is independent of the temperature, calculate c

and the latent heat l in the situation described by the text.
8) A mass m = 50 g of an ideal monoatomic gas is subjected to a reversible isochoric

transformation in which the temperature increases by DT = 160 K. If the enthalpy change is DH = 8310 J, say which gas it is .

9) A homogeneous thin rod with length l = 4.00 m and mass m = 4.00 kg is hinged at
one end with a frictionless hinge. The rod is initially in a vertical position as shown in the figure.

A very small perturbation causes the rod to rotate and fall. When the shaft has covered a quarter of a turn and is in a horizontal position, calculate:
(a) the angular velocity ω of the rod and the velocity vcm of its center of mass;
(b) the ratio between vcm and the speed v that the rod would have if, instead of

rotating, it were in free fall between the same altitudes of the center of mass; (c) the angular acceleration α of the rod.

10) Two homogeneous spheres with radius R = 1.00 cm, having the same mass m = 100
g, descend along an inclined plane, with an inclination θ = 1.72 °. The first sphere slides without

rolling in the absence of any form of friction; the second sphere rolls down without sliding, in

the absence of rolling friction.
Determine the accelerations with which the 2 spheres descend.