Sunday, October 2, 2022

# How Do You Calculate Speed In Physics

## How To Calculate Speed Distance & Time: The Formula Triangle Youll Need

Calculating average velocity or speed | One-dimensional motion | Physics | Khan Academy

To work out speed, divide the distance of the journey by the time it took to travel, so speed = distance divided by time. To calculate time, divide the distance by speed. To get the distance, multiply the speed by time.

You may see these equations simplified as s=d/t, where s is speed, d is distance, and t is time.

This formula can be arranged into the triangle above. In the triangle, speed and time form the base, as they are what is multiplied together to work out the distance.

The triangle is an easy way to remember the formula and can save you time when working out your exam questions. The triangle will help you remember the three formulas:

• The formula of speed is Speed = Distance ÷ Time
• The formula of time is Time = Distance ÷ Speed
• The formula of distance is Distance = Speed x Time

The triangle shows you what calculation you should use. As distance is at the top of the triangle, to work it out, you need to multiply speed with time.

As speed and time are at the bottom of the triangle, you need to divide this number from the figure for distance, to work out the correct answer.

When beginning to study for your practice test, make sure you write out the triangle on your paper. This will help you to memorize it.

## Average Speed Solved Examples

Problem 1: A runner sprints at a track meet. He completes a 1000-meter lap in 1 minute 30 sec. After the finish, he is at the starting point. Calculate the average speed of the runner during this lap?Answer:

Total distance covered by the runner = 1000 meters

Total time taken =1minute 30 sec

= 90 secSo, applying the formula for the average speedwe have,

1000/90

11.1 m/s

Problem 2: A car travels at a speed of 40 km/hr for 2 hours and then decides to slow down to 30 km/hr for the next 2 hours. What is the average speed?Answer:D1 = 40 * 2 = 80 miles

D2 = 30 * 2 = 60 miles

Total distance D= D1+D2

D = 80 + 60

Total Distance travelled/Total Time taken

= 140/4

See the video below, to have a clear idea about average speed, average speed formula, and average velocity.

Hope you learned the average speed definition, average speed formula, how to calculate average speed along with examples. Stay tuned with BYJUS to know more.

## Calculate Speed Distance And Time

When an object moves in a straight line at a steady speed, we can calculate its speed if we know how far it travels and how long it takes. This equation shows the relationship between speed, distance travelled and time taken: Speed is distance divided by the time taken. For example, a car travels 30 kilometres in 2 hours. Its speed is 30 ÷ 2 = 15km/hr.

Formula used :

`Distance  = Speed * TimeTime = Distance / SpeedSpeed = Distance / Time`

Examples:

`Input : distance : 48.5  time : 2.6Output : Speed : 18.653846153Input : speed : 46.0  time : 3.2Output : Distance : 147.2Input : distance : 48.5  speed : 46.0Output : Time : 1.0543`

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## Finding The Dimensional Formula Of Speed

The mathematical representation of speed is:

Dimensional formula of Distance = M0L1T0

M0L1T-1

There are four types of speed and they are:

• Instantaneous speed

Uniform speed: A object is said to be in uniform speed when the object covers equal distance in equal time intervals.

Variable speed: A object is said to be in variable speed when the object covers a different distance at equal intervals of times.

Average speed: Average speed is defined as the uniform speed which is given by the ratio of total distance travelled by an object to the total time taken by the object.

Instantaneous speed: When an object is moving with variable speed, then the speed of that object at any instant of time is known as instantaneous speed.

## How To Calculate The Time To work out the time that the journey took, you will need to know the speed of the journey and the distance that was travelled.

Here is an example:

If the driver travelled 50 miles at 5mph, then to work out the time taken you would divide:

50miles / 5 miles per hour -\> 50 / 5 = 10

The time taken to travel this distance is 10 miles per hour.

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## Scalar And Vector Quantities

Speed is a scalar quantity. It does not have a direction. It only has a size, meaning a magnitude or scale. Scalar quantities can go from 0 to infinitely fast.

A vector quantity has size and direction, as with the movement of an airplane in the sky. Velocity is a vector quantity.

Speed, being a scalar quantity, can never be less than 0 . Average and instantaneous speeds are always scalar quantities, which means you can always measure them with a number. Distance and time are also scalar quantities and can also be measured with numbers.

## Difference Between Speed And Velocity

 Speed

When the car travelled with a certain distance d over time t, we call its speed v.

v=d/t

As you know, sometimes we need to change our direction while driving due to traffic or other reasons in that case, we measure the displacement instead of distance d in time interval t.

The equation becomes the velocity v as,

Displacement is the shortest distance between final and initial distance, but its magnitude is less than or equal to the total distance d.

Distance Vs Displacement

Since speed is nonzero or never decreases with time, the velocity magnitude becomes the speed value when the time approaches zero.

That means speed v tells us how fast the car is. Whereas velocity v tells us both how fast the car is and its direction. Therefore, we called speed as the magnitude of the velocity vector.

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## How To Use The Speed Calculator

Use this speed calculator to find out the value of speed without having to perform manual calculations with the speed formula. Its also known as an average speed calculator, mph calculator, and a time distance calculator. Its a very simple online tool which provides instant results. Here are the steps to follow for this calculator:

• First, input the value of the Distance and choose the unit of measurement from the drop-down menu.
• Then input the value of the time, make sure to be as specific as possible. Also, choose the unit of measurement from the drop-down menu.
• After entering all of the required values, the speed calculator performs the calculation for you to give you the value of Speed.

## The Differences And Similarities Between Average Speed And Average Velocity

How to Calculate Velocity

Similarities Both of these terms are average of some length by the time taken. The SI unit and other standard units of measurement of both average speed and average velocity are the same. The formula used to calculate the average speed and average velocity is virtually the same, v = D/t, s = d/t, with the only slight difference that in the first case direction is to be mentioned.

Differences – Average speed is a scalar and is not affected by the presence or absence of a direction, while average velocity being a vector needs a direction. Average speed takes distance, that is, total length travelled while being measured, while average velocity takes displacement, that is, the straight distance from the original position to the final position.

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## Average Speed Vs Average Velocity

Speed and velocity might seem to be the same thing, but they’re not. Speed is a scalar quantity – it is defined by magnitude only. In simple terms, it tells you how fast an object is moving. On the other hand, velocity is a vector – it is defined not only by magnitude but also by direction. It tells you the rate at which an object changes its position.

Imagine you drove a car 100 meters forward and then 100 meters back. You would drive at a certain average speed in each direction, but you would have zero average velocity, as velocity is measured as the rate at which the position of the car changes, and, overall, the car didn’t change its position. Therefore, it is enough to say that the average speed of a car was 50 mph, but when calculating velocity we would have to add direction, let’s say 50 mph east.

And if you would like to know how fast your speed or velocity was changing you would need to calculate acceleration.

## Introduction To Average Speed And Average Velocity

Before understanding average speed and average velocity, we must first understand the distinction between distance and displacement. The scalar quantity “distance” represents how much ground an object has covered. The shortest distance between two points is represented by displacement, which is a vector quantity. If a particle moves in a circle, for example, the distance travelled after one revolution equals the circumference of the circle, but the displacement is zero.

Let’s have a look at the definitions of speed and velocity.

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## Formula Of Average Speed

The formula for average speed is found by calculating the ratio of the total distance traveled by the body to the time taken to cover that distance.

The average speed equation is articulated as:

Total Distance traveled/Total Time taken

Equation is the formula for an average speed of an object moving at a varying speed.

## Examples On Speed Formula Let us solve some interesting problems using the speed formula.

Example 1: A train covered a distance of 120 km in an hour. Determine the speed of the train in m/s using the speed formula.

Solution:

To find: The speed of the train.The distance covered by a train in meters = 120×1000m = 120000m Time taken by train in seconds = 60×60 = 3600 secondUsing Formula for Speed,Speed = Distance/Time = 120000/3600 = 33.3m/sec

Answer: The speed of the train is 33.3 m/s.

Example 2: A cyclist covers 20 km in 50 minutes. Use the speed formula to calculate the speed of the cyclist in m/s.

Solution: To find: The speed of a cyclist.The distance covered by a cyclist in meters = 20×1000 =20000m Time taken by cyclist in seconds = 50×60= 3000 secondUsing formula for speed,Speed = Distance/Time = 20000/3000 = 6.67m/sec

Answer: The speed of the cyclist is 6.67 m/s.

Example 3: Using the speed formula calculate the speed of a person in kilometers per hour if the distance he travels is 40 kilometers in 2 hours?

Solution:

The formula for speed is Distance = 40 kilometers

Answer: The speed of the person is 20 kilometers per hour.

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## How To Use Speed Formula

Speed formula can be used to find the speed of objects, given the distance and time taken to cover that distance. We can also use the speed formula to calculate the distance or time by substituting the known values in the formula for speed and further evaluating,Distance = Speed × Time or, Time = Distance/SpeedLet’s take a quick look at an example showing how to use the formula for speed.

Example: What is your speed if you travel 3600 m in 30 minutes?

Solution: Using Formula for Speed,

Speed = Distance ÷ TimeSpeed = 3600 ÷ = 2

Answer: Your speed if you travel 3600m in 30 minutes is 2 m/s.

## How To Calculate The Average Speed Of A Car

Say you travelled a certain distance with a car or another vehicle and you want to calculate what its average speed was. The easiest way to do that would be by using the calculator above, but if you prefer, you can also do the math yourself. Either way, you need to know the distance to a satisfactory approximation, for which you can use a map to measure the distance from point to point. Make sure you measure closely to the path you took, and not via a straight line, unless you travelled by air in which case that would be a good approximation. Of course, having a GPS reading of the distance would be more precise. Then you need to know the travel time. Make sure you subtract any rests or stops you made from the total trip duration.

If the total distance travelled was 500 miles and the time it took you was 5 hours, then your average speed was 500 / 5 = 100 miles per hour . If the distance was 300 kilometers and it took you 5 hours to cover it, your speed was 300 / 5 = 60 km/h .

#### Cite this calculator & page

If you’d like to cite this online calculator resource and information as provided on the page, you can use the following citation: Georgiev G.Z., “Speed Distance Time Calculator”, Available at: URL .

##### Transportation calculators

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## How To Calculate Speed Distance & Time

Working out speed, distance and time is an important part of many roles, including those in the armed forces or transport industries.

If you are applying for a role in these industries, you may be tested on this as part of your recruitment process. The questions will allow your employer to test your applied mathematical abilities.

## Rotational Speed And Tangential Speed

Calculating Speed | Forces & Motion | Physics | FuseSchool

Rotational speed, or angular speed, is the number of revolutions over a unit of time for an object traveling in a circular path. Revolutions per minute is a common unit. But how far from the axis an object is its radial distance as it revolves determines its tangential speed, which is the linear speed of an object on a circular path?

At one rpm, a point that is at the edge of a record disk is covering more distance in a second than a point closer to the center. At the center, the tangential speed is zero. Your tangential speed is proportional to the radial distance times the rate of rotation.

Tangential speed = radial distance x rotational speed.

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## How Do You Convert Between Mph And Kph

To convert from miles per hour to kilometres per hour:

• Take your speed.
• Multiply the value by 1.6.
• To convert kilometres per hour to miles per hour:

• Take your speed.
• Multiply the value by 0.62.
• A handy trick if you donât have a calculator to hand is to use the Fibonacci sequence . Take a number, the next one in the sequence is the kilometres if the previous one was miles .

## What Is The Unit For Speed

The unit for speed is distance over time, as it is defined as the amount of time it takes an object to cover a particular distance. The base, or SI, unit is metres per second, but this is not very practical in everyday life. You are likely more familiar with units such as kilometres per hour, miles per hour and knots. Any distance over time is a speed unit, so other units of speed include nanometres per fortnight, Boeing 787s per solar year, or bananas per Friedman.

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## Speed Distance & Time Calculation

In order to use the above speed, distance & time calculator, or do such math on your own, you will need to know two out of three metrics: speed, distance, time. You will need to convert the metrics to the same time and distance units, e.g. miles, kilometers, meters, yards, feet, and hours, minutes or seconds. For example, if you have speed in mph , time should also be in hours. If you have distance in kilometers, then speed should also be in km/h .

The unit of the result will depend on the units you input, but our speed calculator will conveniently display additional units where appropriate.

## S To Get Better At These Questions To improve your skill in answering speed distance time questions, there are two main things you can do.

First, make sure that you are familiar with the formula triangle. The key to answering these questions is knowing the formula inside out, so that you always know what equation to use, whether the exam question is asking you to work out speed or distance.

Secondly, you should focus on improving your general mathematical skills. You may get a compound question, which asks you to use the formula in conjunction with other maths skills to work out the answer to the problem.

You can try a few maths practice tests, such as these, which will help you to practise your basic numeracy skills.

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## How To Calculate Average Speed

To calculate the average speed of an object, you must know the total distance an object travels and the total elapsed time of its whole journey.

The distance/speed/time triangle is handy for calculating this and two other scalar quantities :

The three parts in the triangle are set up in their correct positions mathematically:

• To get average speed,
• Average speed is especially useful because it takes into account the reality of an event, rather than assuming something or someone is moving at a constant speed.

The porpoise could have started slowly, sped up, paused to play, and continued. That three-toed sloth may have stopped for a moment to catch its breath before hurrying onward. You might have to make numerous stops when walking a dog, but in all three cases, you can easily calculate average speed by dividing the total distance traveled by total elapsed time.

## How Fast Am I Going

Speed is not a precise term – there are a few more accurate meanings, and they should not be confused with each other. Let’s consider the differences between instantaneous speed, average speed and rotational speed. For the purpose of two first, we will try to visualize it with an example of driving a car.

You are driving along the long, open highway. You glance down at the speedometer of your car it reads 100 kilometers per hour. From this, you know how far you will drive if you keep the speed constant. We know that, in practice, keeping the speed exactly constant is almost impossible , and our speed fluctuates all the time, more or less. The actual distance you travel in an hour is the average of all these speeds. Conclusion – the average speed is the total distance traveled in a unit of time .

So, what does the number your speedometer indicates really mean? That is your instantaneous speed your speed at this exact moment. According to the textbook definition, the instantaneous speed is the change in object position, x, between two times, tâ and tâ .

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