Speed and Velocity

Science >> Physics of Children Speed ​​and speed are often used interchangeably in everyday life, but they represent different amounts in physics.

Speed ​​is a measure of the speed at which an object moves relative to a reference point. It is not a direction and is regarded as one digit or scalar. Speed ​​can be calculated by the following formula.

In the United States, we will mainly consider the speed of the hourly speed or the speed mile. This is the way to measure the speed of the car. In science and physics, the standard measurement unit of speed is usually meters per second or m / s.

Instantaneous speed - the speed at which an object is in one moment. At this point the car may be driving at 50 miles per hour, but it may slow down or accelerate in the next hour.

Average Speed ​​- Average Speed ​​is calculated from the distance the object moves within a certain amount of time. When the car moves 50 miles per hour, its average speed will be 50 miles per hour. Meanwhile, the car is running at an instantaneous speed of 40 mph and 60 mph, but the average speed is 50 mph.

Speed ​​is the rate of change of the position of the object. Speed ​​has amplitude (speed) and direction. Speed ​​is a vector. The speed is expressed by the following equation.

Speed ​​and speed are the same unit of measurement. The standard measurement unit is m / s or m / s

Speed ​​is the magnitude of speed. Speed ​​is the speed of the object plus its direction. The speed is called a scalar, and the speed is called a vector

The fastest speed in the universe is the speed of light. The speed of light is 299,792,458 meters / second. In physics, this number is represented by the letter "c".

Escape speed of the earth is the speed required to escape from the gravity of the earth. It's 25,000 miles per hour

We have discussed speed and speed and made some calculations. However, speed and speed are important factors, but it will help to provide summary information, but little details. For example, considering data for a 200 meter race in 20 seconds, you can see that the average speed is 10 meters / second. However, I do not know the information on who is the fastest, who is leading 100 meters ahead. This information is important as it determines the strengths and weaknesses of the athletes and also helps to develop training programs for specific players. Acceleration measurement is very important. Acceleration is the rate of change of speed. Therefore, when the acceleration is zero, the speed is constant. Thus, when the object changes speed by decelerating or decelerating or changing direction, it accelerates (or decelerates). The athletes' acceleration varies greatly. So:

By definition, acceleration is the rate of change of time. The speed is a scalar, but the speed is a vector. Speed ​​has size and direction. In the animation below, the velocity vector is shown as an arrow. The direction changes, but the range does not change. Speed ​​when vector bar is not written v is the speed magnitude. By definition, speed is ds / dt. (Refer to Introduction of Calculus.) Since radius r is a constant, v is r × dθ / dt. v is the change rate of the linear position, and dθ / dt is the change rate of the angular position. This is called angular velocity and we use symbol ω. The speed is rω and the direction is tangent.