physics final

physics

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is a branch of science that involves the study of the physical world: energy, matter, and how they are related.

dimensional analysis

treating the units as algebraic quantities

**significant digits**

The valid digits in a measurement

hypothesis

is an educated guess about how variables are related.

scientific method

make observations, do experiments, and create models or theories to try to explain your results or predict new answers.

**scientific law**

a rule of nature that sums up related observations to describe a pattern in nature.

s**cientific theory**

is an explanation based on many observations sup- ported by experimental results.

**measurement**

is a comparison between an unknown quantity and a standard.

**precision**

degree of exactness of a measurement

**Accuracy**

describes how well the results of a measurement agree with the “real” value

**independent variable**

is the factor that is changed or manipu- lated during the experiment.

**dependent variable**

is the factor that depends on the independent variable.

**line of best fit**

The line in blue, drawn as close to all the data points as possible,

**linear relationship**

between the two variables.

**Linear Relationship Between Two Variables**

*y* = *mx* +*b*

**Slope**

*slope*

**Quadratic Relationship Between Two Variables**

when one variable depends on the square of another.

**Inverse Relationship**

A hyperbola results when one variable depends on the inverse of the other.

**motion diagram**

A series of images showing the positions of a moving object at equal time intervals

**particle model**

is a simplified version of a motion diagram in which the object in motion is replaced by a series of single points

**origin**

is the point at which both variables have the value zero.

coordinate system

location of the zero point of the variable you are studying and the direc- tion in which the values of the variable increase.

**position**

he separation between an object and the origin.

**distance**

The length of the arrow indicates how far the object is from the origin

**magnitude**

Quantities that have both size,

vectors

direction

**scalars**

Quantities that are just numbers without any direction, such as distance, time, or temperature

**Time Interval** \n

The difference between two times

**displacement**

is equal to the final position minus the initial position.

**position-time graph**

a horizontal axis and the position data on a vertical axis

**instantaneous position**

the position at a particular instant.

**average velocity**

defined as the change in position, divided by the time during which the change occurred.

**average speed**

how fast the object is moving

**instantaneous**

The speed and direction of an object at a particular instant

**acceleration**

the rate at which an object’s velocity changes

Average Acceleration

is the change of an object in velocity during some measurable time interval divided by that time interval.

**instantaneous acceleration.**

The change in velocity at an instant of time is called The instantaneous acceleration of an

**FinalVelocitywithAverage**

**Acceleration**

The final velocity is equal to the initial velocity plus the product of the average acceleration and time interval.

**Position with Average Acceleration**

An object’s position at a time after the initial time is equal to the sum of its initial position, the product of the initial velocity and the time, and half the product of the acceleration and the square of the time.

**Velocity with Constant Acceleration**

The square of the final velocity equals the sum of the square of the initial velocity and twice the product of the acceleration and the displacement since the initial time.

**free fall**

which is the motion of a body when air resistance is negligible and the action can be considered due to gravity alone.

**acceleration due to gravity**

is the acceleration of an object in free fall that results from the influence of Earth’s gravity.

**force**

is a push or pull exerted on an object.

**free-body diagram.**

physical model, which represents the forces acting on a system

**net force**

the vector sum of all the forces on an object

**Newton’s second law**

the observation that the acceleration of an object is proportional to the net force and inversely proportional to the mass of the object being accelerated

**Newton’s first law.**

his statement, “an object that is at rest will remain at rest, and an object that is moving will continue to move in a straight line with constant speed, if and only if the net force acting on that object is zero,”

**Inertia**

the tendency of an object to resist change.

**equilibrium**

the net force on an object is zero, then the object

**apparent weight**

is the force an object experiences as a result of all the forces acting on it, giving the object an acceleration.

**weightlessness**

means that there are no contact forces pushing up on the object, and the object’s apparent weight is zero.

**drag force**

is the force exerted by a fluid on the object moving through the fluid.

**terminal velocity**

The constant velocity that is reached when the drag force equals the force of gravity

**interaction pair**

is two forces that are in opposite directions and have equal magnitude.

**Newton’s third law**

which states that all forces come in pairs.

tension

name for the force exerted by a string or rope

**normal force**

is the perpendicular contact force exerted by a surface on another object.

**components**

which are a vector parallel to the *x*-axis and another parallel to the *y*-axis.

**vector resolution**

breaking a vector into its components is sometimes

**kinetic friction**

it is exerted on one surface by another when the two surfaces rub against each other because one or both of them are moving.

**static friction**

which is the force exerted on one surface by another when there is no motion between the two surfaces.

**coefficient of static friction**

is the maximum static friction force that must be overcome before motion can begin.