opic: 1.1 Physical Quantities and Measurement Techniques

Scalar Quantity

A quantity that has only magnitude, such as distance or mass.

Vector Quantity

A quantity that has both magnitude and direction, such as force or velocity.

Distance

The total length travelled, measured in units like meters (e.g., 5 m).

Force

A push or a pull acting on an object, measured in newtons (e.g., 20 N downwards).

Speed

The distance travelled per unit time, measured in meters per second (e.g., 10 m/s).

Weight

The force of gravity acting on an object's mass, measured in newtons (e.g., 50 N towards the center of the Earth).

Mass

The amount of matter in an object, typically measured in kilograms (e.g., 15 kg).

Acceleration

The rate of change of velocity per unit time, measured in meters per second squared (e.g., 9.8 m/s² downwards).

Momentum

The product of an object's mass and its velocity, measured in kg m/s (e.g., 30 kg m/s to the right).

Field Strength

The force per unit charge (electric) or mass (gravitational), measured in newtons per coulomb (e.g., 10 N/C left).

Resultant Vector

The vector that results from adding two or more vectors together, representing their combined effect.

Pythagoras' Theorem

A mathematical formula used to calculate the magnitude of the resultant of two perpendicular vectors.

Magnitude

The size or length of a vector, indicating how strong or how much.

Trigonometry

A branch of mathematics used to find angles and distances in triangles, applicable to the direction of vectors.

Parallax Error

An error in measurement caused by viewing an object from an angle rather than straight on.

Micrometer Screw Gauge

An instrument used to measure very small distances with precision, typically in millimeters.

Displacement Method

A way to measure the volume of an irregular solid by using the change in water level when submerged.

Mean Average

The sum of a set of values divided by the number of values, used to reduce random errors.

Pendulum

A weight suspended from a pivot that swings back and forth, commonly used in timing experiments.

Amplitude

The maximum extent of a vibration or oscillation measured from the position of equilibrium.

Acceleration (definition)

The rate of change of velocity over time, expressed as a = (v - u) / t.

Positive Acceleration

When an object’s speed is increasing over time.

Zero Acceleration

A situation where an object maintains a constant speed.

Negative Acceleration

Also known as deceleration; when an object’s speed is decreasing over time.

Resultant Force

The net force acting on an object, which determines its acceleration.

Terminal Velocity

The constant speed that a freely falling object eventually reaches when the resistance of the medium prevents further acceleration.

Gravity

The force that attracts a body towards the center of the earth, or towards any other physical body having mass.

Time Interval Measurement

The process of measuring the duration of events using clocks or timers.

Digital Timer

An electronic device to measure time intervals with precise readings.

Equilibrium Position

The position where the net force acting on an object is zero, resulting in no acceleration.

Stack Measurement

A technique used to find the thickness of a single item by measuring a large number of items and averaging.

Main Scale Reading

The primary reading from a measuring instrument that provides the core measurement value.

Circular Scale Reading

A supplementary reading from a precision measuring instrument that adds fractional measurements.

Fiducial Point

A reference point in a cycle of motion from which measurements are taken consistently.

Average Period

The mean duration of a single cycle of periodic motion calculated from total time divided by the number of cycles.

Maximum Displacement Point

The farthest point from the equilibrium position reached during oscillation.

Eye Level Measurement

Adjusting the viewpoint to avoid parallax error when taking measurements.

Force of Gravity

The gravitational pull acting on an object determined by its mass and the acceleration due to gravity.

Average Thickness Calculation

Determining the average measurement of a single item by dividing the total thickness by the quantity measured.

Submerged Object

An object that is completely below the surface of a liquid, affecting the liquid's level.

Water Level Measurement

Assessing the volume of liquid displaced by an object to find its volume.