Physics Formulas: How to use speed, velocity, and acceleration

Physics Formulas: How to use speed, velocity, and acceleration

Physics is the subject based on different formulas. It mainly contains the concepts of speed, velocity, acceleration, and distance. Everything you see in your surroundings work as perSpeed, velocity and acceleration .png the formulas of Physics. Speed, velocity, and acceleration are the three basic concepts in Physics and every object works on these three concepts. They are the basic physics formulas which you should know for mastering in the subject. Let us discuss in details the relation between Speed, velocity and acceleration.


Speed


Meaning

You may think that Speed and velocity are similar terms, but they are not actually. Speed is the measurement of how a thing moves. You can divide the speed into fast and slow. It has a numerical value.


Formula of speed

We have been learning the average speed formula since the school days.

It is Speed= Distance/ Time.


Average Speed

The average speed of the thing is the distance that the object travels divided by the time taken to travel that distance. It is defined by magnitude. Further, average speed is the change of distance with the time.


Ways to calculate the average speed

Constant speed is an important concept in this formula. If an object moves at a constant speed, the formula for speed will be as under:


Speed= total distance/elapsed time


Mostly, the object travels at different speeds at a particular distance. For example, the speed of the car does not remain the same throughout the journey. It changes in the trip. There are some reasons why the speed of the car changes in the trip such as red light, speed breakers and other obstructions on the road. These hurdles slow down the car’s speed. Then the formula of the average speed of the car will be as under:


Average speed= total distance/ elapsed time


Average speed is measured in units of distance such as miles per hour, meters per second or feet per second.


Examples of average speed

A freight train travels a distance of 160 miles in 4 hours. Calculate the average speed of this train.


Average speed= Total distance/ elapsed time 


160/4 hours = 40 miles per hour


A boy drove 50 miles trip to his aunt’s house in 2 hours. His return trip took 3 hours. Calculate the average speed of this trip.


Average speed = Total distance/elapsed time, Rate=distance/time



Rate(mph)

Time (hr)

Distance(miles)

To 

50/1=50

1

50

Return 

50/2=25

2

50


Average speed= 50(1) + 25(2)/ 1+2 = 50+50/3

100/3= 30.34 mph


Velocity

The next important concept is velocity. It is the rate at which the thing or object changes its position. It can be defined both in numerical value and direction.


The average velocity formula is the distance covered divided by speed + direction of travel.

Let us have a look at the problems of velocity.


A person walked 6 km in just 2 hours and 3 km in just 1 hour in the same direction. Calculate the man’s average velocity for the journey.


Average velocity= distance/time= 6 km+ 3 km/2 hours + 1 hour= 9km/3 hours = 3km/h


A man begins to walk from a point on a circular field of radius 1.5 km and after 2 hours you are at the same point. Calculate the average velocity for this journey.


Average speed= distance/time= circumference/time= 2*1.5*3.14/2 hours= Pi km/h= 3.14 km/h.


If you walk in a circular area and come back to the same point where you began walking, the displacement will be zero. Then the average velocity will also be zero.


A car goes to the east direction for 120 meters in 6 seconds and then turns towards the west direction for 60 meters in 2 seconds. Calculate the average velocity.


Distance= 120 meters + 60 meters= 180 meters

Displacement= 120 meters – 60 meters= 60 meters, to east

Elapsed time= 6 seconds + 2 seconds= 8 seconds

Average velocity= Displacement/ time elapsed= 60 meters/ 8 seconds= 7.5 meters/second.


Acceleration

The third important concept in Physics is Acceleration. Acceleration is the measurement of the change in velocity of a particular object at a certain time. The time is normally 1 second. Further, the velocity of the object may increase or decrease at a certain time.


Acceleration Formula

It is measured in meters/second squared.


When an object changes velocity by time, it is known as constant acceleration. When an object changes the velocity by decreasing, it is known as Negative acceleration. 


There are 2 equations for acceleration. The first formula includes force, mass, and acceleration which is as under:

F=ma

The second formula is as under:

Acceleration= change in velocity/ change in time


Examples

Calculate the acceleration of the object moving with uniform velocity.


When there is uniform velocity, the initial and final velocities are equal to V. The formula is as under:

Average acceleration= change in velocity/ change in time.

So, the acceleration of the object traveling at a constant velocity is zero.


The speed of the car decreases from 75 km/h to rest in 30 seconds. Calculate the acceleration of the car in m/s2.


The initial velocity of the car is 75km/h and the final velocity is 0. 

Average acceleration= 0-75 km/h/ 30 seconds= 

We should now convert 75 km/h into m/s as under:

75 * 1000m/ 3600 s= 20.83 m/s

Average acceleration= -20.83m/s / 30 seconds= -0.69 m/s2


A car has a constant velocity of 60 km/h accelerates for 36 seconds at 1.5 m/ s2. Calculate the velocity of the car at the end of 36 seconds of acceleration.


Solution: The initial velocity of the car is 60 km/h. 

Average acceleration= 1.5 m/s2= V- 60 km/h/ 36 seconds


Equation is as under:


V – 60km/h= 1.5m/s2 * 36 seconds= 54 m/s

We have to now convert 54 m/s into km/h

54 m/s= 54 m *(1km/1000m) / (1s * 1h/3600s)

          = 54 * 3600 / 1000 km/h= 194.4 km/h

V = 194.4 km/h + 60 km/h= 254.4 km/h.


Interesting facts you may not know about speed, velocity, and acceleration.

The first scientist to measure the speed was Galileo.


Gravity is related to acceleration. The object falling towards the earth has increasing acceleration and low speed. It is because of earth’s gravity.


The speed of the light is fastest in the universe.


Newton stated that the Kinetic energy of a traveling object is linear and the square of the velocity. The velocity of the thing is changed by the mass of the thing.


Best ways to learn Physics easily


If you are finding Physics a bit tough, you can try these methods to learn effectively.


Gaining mastery in basic concepts

To be an expert in this subject, you have to remember all the basic physics formulas properly. You should be master in knowing the Central theories of physics. These theories will make it simpler for you to solve even the mathematical problems. Central theories are also used in the physical world to a large extent.


Learn more math

Math is directly related to physics. There are some mathematical problems which you need to learn to further learn physics more perfectly. You have to gain expertise in the equation for velocity and other formulas. You can learn math and physics simultaneously for better understanding.


Remember basic equations

Physics basically describes the relationship between speed, velocity, force, and acceleration. With these concepts, you can solve every easy or difficult problem of physics. You have to memorize the average speed formula and velocity formula for solving the problems. Learning basic equations will make the subject easier and simpler for you.


Derivations

While solving the problems of physics, it is important to understand the working of it. You should go through each step of the problem and understand how it is derived. Here, you should be well versed again with the basic equations of physics.


Know the important steps in every problem

Physics is all about important steps which should arrive while solving problems. If you want to get good scores in exams, you should put stress on important steps in the problems. The steps which are not important should be avoided. You should explain each step of the problem in a precise way in physics exam.


Draw and understand

Physics can be easily learned by the way of graphs and drawings. You can draw and get a better understanding of the concepts in detail. In exams, you can show the concepts with the help of drawings. This will gain you a good score in the paper.


Make easier each problem of physics

Most of the students find the problems of physics very difficult at first look at exams. But, it is not so because analysis of the problem is the best way to solve each problem. The students should study and analyze the problems properly and find the steps which are easier to get an answer. 


Flashcards

Just like kids who learn alphabets by way of flashcards, you can also learn physics. You can use flashcards to remember the basic physics formulas and other concepts. They can also learn the units and principles of physics with the help of flashcards.


Take more interest in the subject

You may find it boring but physics is the subject where your participation counts a lot. You should discuss various physics formulas and basic concepts with your teachers and friends which will clear all your doubts. The discussion will help you in a better understanding of the subject.


Look at the syllabus

Before physics exam, you should go through the full syllabus of the subject. You should have a glance at all the chapters of the subject and take important notes and aspects first. This will automatically make your work much better. Then you can jump on the most difficult sections of the subject.


Review of the chapters

After the physics lecture, one should go through the chapters taught in the class. You should revise the lessons and ask the doubts if any to the teachers or students. You can also discuss the formulas and lessons with your friends after school.


Practice more

As we discussed earlier, physics and math are related. Just as you practice math problems each day, you should also practice physics problems so that at the moment of the exams, you do not get any doubts. 


Download apps

Today, smartphones do more work than other ways. You can download physics app and learn basic physics formulas via apps. The students will enjoy learning the subject more with the help of apps. The experts also show the steps of solving physics problems through apps.


Watch online videos

YouTube will make physics a more interesting subject for you. You can also take help of online lectures given by tutors from various parts of the world. Some of the best lecturers from the world will teach you the concepts, principles, and formulas in a professional manner.


Take crash courses

You can opt for crash courses in any class or private institution. You can know the subject in depth with these courses. They also make a schedule and cover the syllabus in proper time. They conduct tests and exams to know the subjects in a proper manner.


Additionally, the other ways to learn physics include experiments, podcasts, and other educational sites. They make the subject simpler and easier to understand.


Conclusion

These are the basic physics formulas and the ways in which you can learn the subject easily. You should first revise and reviews the chapters taught in the class. You can then take the help of all the latest ways and techniques to learn the concepts, principles, and units.


Physics is thus a subject of equations, problems, and mathematical expressions which can be enjoyed with various methods. 

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