2022 | Resumo da Aula | 1ª Série | Matemática | Aula 2 - Sistema Internacional de Unidades (SI) II

Summary

In this educational video, Professor Eliane introduces the International System of Units (SI), focusing on the seven base quantities: length, mass, time, temperature, electric current, amount of substance, and luminous intensity. She explains the derived quantities and their corresponding units, such as area (m²), volume (m³), and speed (m/s). The video also provides examples, like calculating the maximum area for a house construction and determining the speed of a runner. Overall, the video aims to simplify the understanding of SI units and their practical applications in everyday life.

Takeaways

• 😀 The International System of Units (SI) is based on seven fundamental quantities: length, mass, time, temperature, electric current, amount of substance, and luminous intensity.
• 😀 The respective units for these quantities are: meter for length, kilogram for mass, second for time, kelvin for temperature, ampere for electric current, mole for the amount of substance, and candela for luminous intensity.
• 😀 Derived quantities are based on the fundamental quantities and use derived units. Examples include area (m²), volume (m³), speed (m/s), and acceleration (m/s²).
• 😀 Not all derived units have a clear name or symbol, but they are used to express products or ratios of the base units.
• 😀 Examples of derived units with specific names include force (newton, N), pressure (pascal, Pa), electrical charge (coulomb, C), and power (watt, W).
• 😀 A real-world application was discussed: calculating the maximum area of a rectangular land for building, factoring in specific land boundaries and constraints.
• 😀 The maximum area of the house that can be built on a 10m by 25m plot, respecting given restrictions, is calculated as 133 square meters.
• 😀 A speed conversion example showed how to convert from kilometers per hour (km/h) to meters per second (m/s), with 18 km/h equal to 5 m/s.
• 😀 The video explains that the SI system of units is important for standardizing measurements in science, engineering, and daily life.
• 😀 The script emphasizes the importance of understanding both base and derived units to solve practical problems in various fields.

Q & A

What is the International System of Units (SI)?

The International System of Units (SI) is a system of measurement based on seven fundamental quantities. These are length, mass, time, temperature, electric current, amount of substance, and luminous intensity.

What are the seven base quantities in the SI system?

The seven base quantities in the SI system are: length, mass, time, temperature, electric current, amount of substance, and luminous intensity.

What is the SI unit for length?

The SI unit for length is the meter (m).

What is the SI unit for mass?

The SI unit for mass is the kilogram (kg).

What is the SI unit for time?

The SI unit for time is the second (s).

What are derived quantities in the SI system?

Derived quantities are those that are defined in terms of the base quantities. For example, area, volume, speed, and acceleration are derived quantities, and they have units derived from the base units.

Give an example of a derived unit and explain it.

An example of a derived unit is speed, which is measured in meters per second (m/s). It is derived from the base units of length (meter) and time (second).

What is the derived unit for force, and how is it expressed?

The derived unit for force is the Newton (N), and it is expressed as kg·m/s², which is the product of mass (kilogram) and acceleration (meters per second squared).

What is the unit of pressure, and how is it derived?

The unit of pressure is the Pascal (Pa), and it is derived as kg/m·s², which represents force (in Newtons) divided by area (in square meters).

How do you convert a speed of 18 km/h to meters per second?

To convert 18 km/h to meters per second, we use the conversion factor where 1 meter per second equals 3.6 kilometers per hour. By dividing 18 km/h by 3.6, we get 5 meters per second.