Physics Review Flashcards

Flashcards from Physics Lecture Notes

What determines how an object's motion changes when it interacts with other objects or systems?

Internal mass.

What determines the strength of gravitational interaction with other objects/systems or gravitational field?

Gravitational mass.

What property do objects/systems have that is experimentally verified to be the same and satisfy conservation principles?

Inertial mass.

What property does matter have?

Resistivity.

What does a vector field give as a function of position?

Values of a physical quantity described by a vector.

What does a gravitational field 'g' at the location of an object with mass 'm' cause?

A gravitational force of magnitude mg exerted on the object in the direction of the field.

How does the gravitational field caused by a spherically symmetric object vary outside the object?

As the inverse square of the radial distance from the object's center.

What quantities can describe the motion of an object in a particular reference frame?

Position, displacement, distance, velocity, speed, and acceleration.

How are forces described?

By vectors.

What accompanies a force exerted on an object?

Interaction of that object with another object.

What happens when one object exerts a force on a second object?

The second object exerts a force of equal magnitude on the first object in the opposite direction.

What is the net force if an object interacts with other objects?

The vector sum of the individual forces.

What are free body diagrams useful for?

Visualizing forces exerted on a single object and writing the equations that represent a physical situation.

What kind of motion can restoring forces result in?

Oscillatory motion

What force describes the interaction of one object with mass and another object with mass?

Gravitational force.

What force results from the interaction of one object with electric charge and another with electric charge?

Electric force.

What kind of forces result from the interaction of one object touching another?

Contact forces.

What does the change in momentum of an object depend on?

The force exerted on the object; direction of the net force exerted on the object.

Over what does the change in momentum of an object occur?

A time interval.

What does the change in kinetic energy of an object depend on?

The force exerted on the object, and the displacement of the object during the interval that the force is exerted.

What force component results in torque about an axis?

The force component perpendicular to the line connecting the axis of rotation and the point of application of the force.

What does the presence of a net torque cause?

A rigid system to change its rotational motion, or an object to change its rotational motion about that axis.

What can a torque exerted on an object change?

The angular momentum of the object.

On what scales are gravitational forces exerted, and on what scales do they dominate?

Gravitational forces are exerted on all scales, and dominate the largest distance and mass scales.

How can the linear motion of a system be described?

By the displacement, velocity, and acceleration of its center of mass.

If interacting objects are parts of the same system, what happens to the center of mass velocity?

There will be no change in the center of mass velocity of that system.

How is the change in linear momentum for a constant mass system calculated?

The product of the mass of the system and the change in velocity of the center of mass.

How is the change in linear momentum of the system given?

By the product of the average force on the system and the time interval during which forces exerted.

What forms of energy are included in the energy of a system?

Kinetic energy, potential energy, and microscopic internal energy.

When is mechanical energy transferred into or out of a system?

When an external force is exerted on a system such that the component of the force is parallel to its displacement.

What is the process through which energy is transferred called?

Work.

What can torque, angular velocity, angular acceleration and angular momentum be characterized as?

Positive or negative depending upon whether they give rise to or correspond to counterclockwise or clockwise rotation with respect to an axis

What may change the angular momentum of the system?

Interactions with other objects or systems.

How is the change in angular momentum derived?

Given by the product of the average torque and the time interval during which torque is exerted.

What is conserved for all systems under all circumstances?

Energy, charge, linear momentum, and angular momentum.

What qualities are constant for an isolated or closed system?

Conserved quantities are constant.

What is an open system?

One that exchanges any conserved quantity with its surroundings.

What does an interaction describe?

A force exerted by objects outside the system or the transfer of some quantity with objects outside the system.

What is the purpose of a boundary between a system and its environment?

To simplify or otherwise assist in analysis.

Classically, what kind of energy can an object have?

Kinetic energy, since potential energy requires an interaction between two or more objects.

What kind of changes can a system with internal structure have?

Changes in internal energy.

When does potential energy exist within a system?

If the objects within that system interact with conservative forces.

What does the internal energy of a system comprise?

The kinetic energy of an objects that make up a system and potential energy of the configuration of the objects that make up the system

Describe energy that can be transferred by an external force exerted on an object or system that moves the object or system through a distance.

Energy that can be transferred by an external force exerted on an object or system that moves the object or system through a distance, this energy transfer is called work. Energy transfer is mechanical or electrical systems may occur at different rates -

What does Kirchhoff's Loop Rule describe?

Conservation of energy in electrical circuits.

What does Kirchhoff's Junction Rule describe?

The conservation of electric charge in electrical circuits.

What is conserved in a collision between objects?

Linear momentum.

What is the same before and after in an elastic collision?

Kinetic energy.

What is the same before and after in an inelastic collision?

Linear momentum is conserved, but kinetic energy is not the same.

What cannot be changed by an interaction within the system?

The velocity of the center of mass of the system.

What happens to the angular momentum of the system if the net external torque exerted on the system is zero?

The angular momentum of the system does not change.

What determines the angular momentum of a system?

The locations and velocities of the objects that make up the system.

What can changes in the radius of a system or in the distribution of mass within the system result in?

Changes in the systems rotational inertia and hence its angular velocity and linear speed for a given angular momentum

Can waves transfer energy and momentum from one location to another?

Yes, without permanent transfer of mass.

How can waves propagate?

Via different oscillation modes such as transverse and longitudinal.

What do mechanical waves require for propagation?

A medium, while electromagnetic waves do not.

What is the amplitude of a wave?

The maximum displacement of a wave from its equilibrium value.

On what does the energy carried by a wave depend?

Amplitude.

What is the period of a periodic wave?

The repeat time of the wave.

What is the frequency of a periodic wave?

The number of repetitions of the wave per unit time.

What is the wavelength of a periodic wave?

The repeat distance of the wave.

What determines whether the observed frequency of a wave depends?

On the relative motion of the source and observer.

What is superposition?

When two pulses cross they travel through each other they do not bounce off each other whereas posts overlap the resulting displacement can be determined by adding the displacement of the other two pulses, this is called superposition

What are standing waves?

Standing waves are the result of the addition of incident and reflected waves that are confined to a region and have the nodes and anti notes

What determines the possible wavelengths of a standing wave?

The size of the region to which it's confined.

When do beats arise from addition of waves?

Waves of slightly different frequency.

Motion is relative, meaning what?

That the motion of any object of interest depends on the point of view of the observer.

What does a reference frame include?

An object of reference with a specific point of reference on it. A coordinate system which includes one or more coordinate axes such as xyz and an origin located at the point of reference the coordinate system including a unit of measurement. A clock which includes and origin in time called t=0 and a unit of measurement for specifying times and time intervals.

What does the linear motion model assume?

That an object considered as a point-like object moves along a straight line.

What is time?

The reading on a clock or some other time measuring instrument.

What is Time interva?

Timer interval delta t is the difference of two times. In the sis system the unit of time and of time interval is second. Other units are minutes, hours, and days, and years. Time and time interval are scalar quantities.

What is X

X represents the displacement xf - xi is the x-scalar component of displacement and is abbreviated to dx or x=position

What can the quantity that appears on the vertical axis of the graph represent?

The position of an object whose actual position is changing along an horizontal axis. The position on the vertical axis does not mean the object is moving in the vertical direction

How can the component of velocity along the axis of motion be found?

As the slope of a position vs. time graph.

What does the position equation represent?

Constant velocity linear motion.

What does a horizontal line mean on a position time graph?

That the object is at rest the position is constant with the time, the same horizontal line on the velocity vs time graph means that the object is moving at a constant velocity

How is displacement determined from a velocity vs. time graph?

As the area between the graph line and the time axis.

What is instantaneous velocity?

Velocity at a specific time.

What is Acceleration ?

Acceleration = delta v/delta t

How is Acceleration measured?

Unit m/s^2

What does the sign of displacement indicate?

Areas below the time axis are negative, and areas above are positive.

What do you need to determine the position of an object at any later time t?

Provided we also know the initial velocity v0x of the object and its constant acceleration ax

In what situations is the alternate equation for linear motion with constant acceleration (2a(x-x0)=v^2x-v^2ox) useful?

In situations in which you do not know the time interval during which the changes in position and velocity occurred.

When is an object in a state of free fall?

Even when it is thrown upward because its acceleration is the same on the way up as on the way down.

What is termed the 'system'?

The object that we choose to analyze.

What is termed the environment?

Everything outside that system is called its environment and consists of objects that might interact with the system, (touch, push or pull) and affects its motion through the external forces

What is the SI unit for force?

Newton (N).

Should the resultant vector be included in the force diagram for the object

It should never be included.

What is the characteristics of force?

Force is a physical quantity that characterizes an interaction between two objects its direction and magnitude for a force to exist there must be two objects that interact just like a hug requires the interaction of two people. Force does not reside in an object.

What do the velocity change arrow in an object's motion diagram points in?

The same direction as the sum of forces that other objects exert on it. If the sum of the forces points in the same direction as the system objects velocity the object speeds up if it is in the opposite direction it slows down if the sum of the forces is zero the object continues with no change in velocity

What is an inertial reference frame?

One in which an observer sees that the velocity of the system object does not change if no other objects exert forces on it or if the sum of all the forces exerted on the system object is zero.

What is Newton's first law of motion?

For an observer in an inertial reference frame when no other objects exert forces on a system object or when the forces exerted on the system object add to zero, the object continues moving at constant velocity( including remaining at rest) inertial is the phenomenon in which a system object continues to move at constant velocity when the sum of the forces exerted on it by other objects is zero

What does mass 'm' characterize?

The amount of matter in an object when the same unbalanced force is exerted on two objects the object with greater mass has a smaller acceleration. The unit of mass is called the kg mass is a scalar quantity and masses add as scalars

What is Newton's second law?

The acceleration of a system object is proportional to the vector sum of all forces being exerted on the object and inversely proportional to the mass of the object

In what direction does the acceleration of a system object points?

In same direction as the vector sum of the forces

What is the radial direction component form of Newton's law?

a=sumF/m or ma=sumF

What is the magnitude of the gravitational force that Earth exerts on any object?

Fe on o=mog

What is object 2 in turn?

Object 2 in turn exerts an equal magnitude oppositely directed force on object 1

Are these forces exerted on the same objects?

These forces are exerted on different objects and cannot be added to find the sum of the forces exerted on an object

When does kinetic friction force occur?

When and object slides along a surface, the surfaces exert kinetic friction forces on each other theses forces are exerted parallel to the contacting sufaces and oppose the motion of the surface relative to the other surface. The kinetic friction force depends on the surfaces themselves and the magnitude of the normal force exerted on on surface than the other