物理学の基礎

Many familiar physical quantities can be specified completely by giving a single number and the appropriate unit. For example, "a class period lasts …

Vector multiplication of two vectors yields a vector product, with the magnitude equal to the product of the individual vectors multiplied by the sine of …

To define some physical quantities, there is a need to specify both magnitude as well as direction. For example, when the U.S. Coast Guard dispatches a …

A physical quantity is defined either by specifying its measurement method or by stating how it is calculated from other measurements. For example, …

Scientists typically make repeated measurements of a quantity to ensure the quality of their findings and to evaluate both the precision and the accuracy …

In any measurement, the precision of the measuring tool is an essential factor. An ordinary ruler, for example, can measure length to the closest …

Scientists always try their best to record measurements with the utmost accuracy and precision. However, sometimes errors do occur. These errors can be …

The position of an object defines its location relative to a convenient frame of reference at any particular time. A frame of reference is an arbitrary …

To describe the motion of an object, one should first be able to describe its position (where it is at any particular time). More precisely, the position …

Mass and weight are often used interchangeably in everyday conversation. For example,  medical records often show our weight in kilograms, but never …

Newton's second law is closely related to his first law of motion. It mathematically gives the cause-and-effect relationship between force and changes …

Tension is a force along the length of a medium, in particular, a force carried by a flexible medium, such as a rope or cable. The word "tension" …

In the years before Newton, a general belief prevailed that different laws governed objects in the sky than objects on Earth. When Kepler wrote down the …