Physics Review: Mechanics, Fields, Circuits, and Nuclear Physics

Comprehensive vocabulary flashcards covering kinematics, forces, energy, fields, electromagnetism, and nuclear physics.

Scalar quantities

A physical quantity that has magnitude only.

Vector quantities

A physical quantity that has both magnitude and direction.

Accuracy

Refers to how close a measured value is to the true value.

Precision

Refers to how close the repeated measured values are to each other.

Random errors

Errors that have different magnitude and signs when measurements are repeated.

Systematic errors

Errors that have the same magnitude and sign when measurements are repeated.

Hooke's Law

States that the extension of a body is proportional to the applied load (force), provided the limit of proportionality is not exceeded ($F = kx$).

Moment of a force about a pivot

The product of the force and the perpendicular distance of the line of action of the force from the pivot.

Couple

A pair of forces which tends to produce rotation only.

Torque of a couple

The product of one of the forces and the perpendicular distance between the lines of action of the forces.

Principle of moments

For an object to be in rotational equilibrium, the sum of clockwise moments about any axis must equal the sum of anticlockwise moments about that same axis.

Distance

The total length moved by an object irrespective of the direction of motion.

Position

Location relative to a reference point.

Displacement

The shortest linear distance from the initial position to the final position with a specific direction.

Speed

The rate of change of distance travelled.

Velocity

The rate of change of displacement.

Acceleration

The rate of change of velocity.

Inertia

The tendency for bodies to resist changes in motion.

Mass

A property of a body which resists change in motion.

Linear Momentum

The product of an object's mass and its velocity.

Newton’s 1st Law of Motion

A body will continue in its state of rest or move with uniform velocity unless a resultant force acts on it.

Newton’s 2nd Law of Motion

The resultant force acting on a body is proportional to the rate of change of its momentum, and the change takes place in the direction of the resultant force.

Newton’s 3rd Law of Motion

If body A exerts a force on body B, then body B exerts a force of the same type, of equal magnitude, but in the opposite direction on body A.

Principle of conservation of energy

States that energy cannot be destroyed or created; it can only be converted from one form to another.

Work done by a force

Defined as the product of the force and the displacement of the body in the direction of the force.

Gravitational field strength at a point

The gravitational force per unit mass on a mass placed at that point.

Electric field strength at a point

The electric force per unit charge on a positive charge placed at that point.

Power

The rate of energy transfer.

Impulse

The product of the force and the time during which the force acts.

Principle of Conservation of Momentum

The total momentum of a system of objects remains constant provided no resultant external force acts on the system.

Newton’s Law of Gravitation

Two point masses attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them.

Electric currents

The rate of flow of charge.

Electromotive force (EMF)

The energy converted from other forms to electrical energy per unit charge passing through the source.

Potential difference across a device

The electrical energy converted to other forms of energy per unit charge passing through that device.

Resistance of a circuit component

The ratio of potential difference across the component to the current in it.

Force field

A region of space in which a body experiences a force without physical contact with another body, produced by the presence of another body.

Magnetic Field

A region of space where a permanent magnet, moving charge, or current-carrying conductor may experience a magnetic force.

Magnetic Flux Density of a magnetic field

Defined as the force per unit current per unit length on a conductor placed perpendicular to the magnetic field.

The $\alpha$-particle Scattering Experiment arrangement

An experimental setup in a vacuum where a beam of positively charged alpha particles (Helium nuclei) is fired through a slit at a thin gold foil, with a detector rotatable to various scattering angles $\theta$ to observe particle deflection.

One mole of substance

An amount of substance containing $6.02 \times 10^{23}$ particles.

Isotopes

Atoms that have the same number of protons but different number of neutrons.

Unified atomic mass unit

One twelfth the mass of the carbon-12 atom.

Binding energy of a nucleus

The minimum energy required to completely separate a nucleus into its constituent neutrons and protons.

Nuclear fission

The disintegration of a heavy nucleus into two lighter nuclei of approximately equal masses.

Nuclear fusion

The combining of two light nuclei to produce a heavier nucleus.

Radioactive decay

The spontaneous emission of particles and/or radiation from an unstable nucleus so it becomes more stable.

Scalar quantities

A physical quantity with magnitude only.

Vector quantities

A physical quantity that has both magnitude and direction.

Accuracy

Refers to how close a measured value is to the true value.

Precision

Refers to how close the repeated measured values are to each other.

Random errors

Errors that have different magnitude and signs when measurements are repeated.

Systematic errors

Errors that have the same magnitude and sign when measurements are repeated.

Hooke's Law ($F = kx$)

The extension of a body is proportional to the applied load (force), provided the limit of proportionality is not exceeded.

Moment of a force about a pivot

The product of the force and the perpendicular distance of the line of action of the force from the pivot.

Couple

A pair of forces which tends to produce rotation only.

Torque of a couple

The product of one of the forces and the perpendicular distance between the lines of action of the forces.

Principle of moments

For an object to be in rotational equilibrium, the sum of clockwise moments about any axis must equal the sum of anticlockwise moments about that same axis.

Distance

The total length moved by an object irrespective of the direction of motion.

Position

The location of an object relative to a reference point.

Displacement

The shortest linear distance from the initial position to the final position with a specific direction.

Speed

The rate of change of distance travelled.

Velocity

The rate of change of displacement.

Acceleration

The rate of change of velocity.

Inertia

The tendency for bodies to resist changes in motion.

Mass

The property of a body which resists change in motion.

Linear Momentum

The product of an object's mass and its velocity.

Newton's 1st Law of Motion

A body will continue in its state of rest or move with uniform velocity unless a resultant force acts on it.

Newton's 2nd Law of Motion

The resultant force acting on a body is proportional to the rate of change of its momentum, and the change takes place in the direction of the resultant force.

Newton's 3rd Law of Motion

If body A exerts a force on body B, then body B exerts a force of the same type, of equal magnitude, but in the opposite direction on body A.

Principle of conservation of energy

States that energy cannot be destroyed or created; it can only be converted from one form to another.

Work done by a force

The product of the force and the displacement of the body in the direction of the force.

Gravitational field strength at a point

The gravitational force per unit mass on a mass placed at that point.

Electric field strength at a point

The electric force per unit charge on a positive charge placed at that point.

Power

The rate of energy transfer.

Impulse

The product of the force and the time during which the force acts.

Principle of Conservation of Momentum

The total momentum of a system of objects remains constant provided no resultant external force acts on the system.

Newton's Law of Gravitation

Two point masses attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them.

Geostationary Satellites

Satellites positioned at a fixed position above the equator that remain stationary above the same point on Earth; ideal for communications and weather monitoring, but have lower spatial resolution and cannot observe latitudes greater than $60^\text{--}70^\text{o}$ North or South.

Electric current

The rate of flow of charge.

Electromotive force (EMF)

The energy converted from other forms to electrical energy per unit charge passing through the source.

Potential difference across a device

The electrical energy converted to other forms of energy per unit charge passing through that device.

Resistance of a circuit component

The ratio of potential difference across the component to the current in it.

Force field

A region of space in which a body experiences a force without physical contact with another body, produced by the presence of another body.

Magnetic Field

A region of space where a permanent magnet, moving charge, or current-carrying conductor may experience a magnetic force.

Magnetic Flux Density of a magnetic field

The force per unit current per unit length on a conductor placed perpendicular to the magnetic field.

One mole of substance

An amount of substance containing $6.02 \times 10^{23}$ particles.

Isotopes

Atoms that have the same number of protons but a different number of neutrons.

Unified atomic mass unit

One twelfth the mass of the carbon-12 atom.

Alpha-particle Scattering Experiment Apparatus

Experimental arrangement used to study the scattering of $\alpha$-particles by firing a beam of positively charged helium nuclei from a source through a slit onto a thin gold foil in a vacuum, detected at various scattering angles $\theta$.

Undeflected Alpha Particles (Scattering Result)

Observation that most particles passed through undeflected or with small deflection, showing that the atom consists of mostly empty space.

Large-Angle Alpha Deflection ($< 1\%$)

Observation that a small fraction of particles are deflected through large angles, demonstrating that all positive charges are concentrated as a nucleus in a small region of space compared to atomic diameter.

Backwards Alpha Reflection ($\approx 180^\circ$)

Observation that a few particles reflect backwards through an angle close to $180^\circ$, proving that the nucleus is small and very massive.

Binding energy of a nucleus

The minimum energy required to completely separate a nucleus into its constituent neutrons and protons.

Nuclear fission

The disintegration of a heavy nucleus into two lighter nuclei of approximately equal masses.

Nuclear fusion

The combining of two light nuclei to produce a heavier nucleus.

Radioactive decay

The spontaneous emission of particles and/or radiation from an unstable nucleus so it becomes more stable.