In most cases, we must compute the velocity and speed of a particle in a specific period. However, there are occasions when we are keener in the velocity number at a certain moment in time for a relatively short time. This can be calculated as the average velocity. We may reduce the time to get it closer to zero., which is instantaneous velocity. With examples, we’ll go over the topic in this article.
The world is moving, people and objects are constantly in motion. But it is only taken note of and scientifically appreciated when we study subjects like physics. Imagine this: you’re in a car racing on the highway. You see the traffic instructions for the speed limit as you go, and you check the speedometer. You take a quick reading and adjust your speed accordingly. Did you know that the quick reading you took is an example of instantaneous Velocity? At that moment in time, the speed happened to be x. However, if you were to take the average of all the speedometer readings you take over a time that would give an average reading. Now that the difference between average and instantaneous is evident, let’s focus on defining average velocity and instantaneous velocity.
The displacement of an object concerning time in a particular direction is termed velocity. Its standard unit is metres per second. Cm per second can also be used to express the magnitude of velocity. The direction of the vector of velocity can also be expressed in different ways, according to the number of dimensions that are involved. For most people velocity means the speed at which something is travelling. That is indeed correct. Velocity means how quick or slow something is moving. In everyday life, this is a common description of velocity but scientists disagree say that such description used to describe velocity is in actual speed and that there is a difference between velocity and speed.
Let us now discuss the difference between velocity and speed.
What is speed? The rate of displacement of an object or particle over a while is termed speed. in layman’s terms speed means the distance that you travel divided by the time taken to travel that amount of distance. It is all about how fast or slow the displacement is. but it has nothing to do with the direction that an object or particle is travelling.
Velocity is concerned with the direction of the displacement of an object. It is also about the speed but the direction is also concluded. For example, speed can be described as 12 km per hour. An example of velocity on the other hand is 12 kilometres per hour East. in the real world, people ignore how important it is to include direction in the measurement of velocity. hence the words velocity and speed are often used interchangeably.
The formula for Instantaneous Velocity measurement
“As the difference in time approaches zero,Vint can be defined as the total displacement of an object or particle divided by total time. The displacement approaches zero as well, but the ratio of movement relative to time reaches a non-zero limit, which is known as instantaneous velocity.” It’s calculated in the same method as average velocity, except the time frame is converged here.
Vint = limΔt→0Δx / Δt = dx / dt
- An extremely short time interval is denoted by Δt.
- The instantaneous velocity here means Vi.
- The displacement of the object is denoted by S.
- T is the time it takes for the displacement to occur.
You can’t understand the concept of physics correctly without solving the problem and cranking the underlying mathematical concepts. Let’s look at some questions on the same.
Exercise 1:
Rockets fired in space move in a straight line, and their equation is as follows: S (t) = 4t + 6t2. If you want to move for 15 seconds before the collision, find the instantaneous velocity at 10 seconds.
Solution: The equation of motion is known:
S (t) = 4t + 6t2
(S is the distance to be displaced or covered.)
dS / dt = d / dt (4t + 6t2) = 4 + 12t
So, instantly (t = 10) = 4 + (12 x 10) = 124 m / s.
Apparently, this bullet is flying at an astonishing speed.
Task 2:
The object is released because it is under the influence of gravity. The approximate equation of motion is given by S (t) = 4.9t2. What is the instantaneous velocity of the body 5 seconds after release?
Solution: In this case, the equation of motion is: The instantaneous velocity at
S (t) = 4.8 t2
t = 5s is given by the following equation.
V instantaneous = [dS / dt] t = 5 = [d / dt (4.9 t2)] t = 5
= [4.9 x 2 xt] t = 5 = 4.9 x 2 x 5 = 49 m / s
The following is an overview of how to resolve these issues. To find the instantaneous velocity, you first need to create or know the equation of motion (relationship between displacement and time and distance variables). Taking the first derivative gives the equation of velocity. Substituting the value of the time variable will give you the velocity value you need at that point.
Conclusion
Physics forms an integral part of all defence exams and to score good marks, it is very essential to get a grasp on the basics. Read through the article thoroughly to gain a proper understanding of what instantaneous velocity means and its fundamental concepts. Practice questions related to the topic, since they are asked in the exam. Through practice, you can compete to the standard the exam demands, and a thorough conceptual understanding is not just a win-win scenario when it comes to exams but also incredibly inevitable.