Speed Formula

The speed formula can be defined as the rate at which an object covers some distance. Speed can be measured as the distance traveled by a body in a given period of time. The SI unit of speed is m/s. In this section, we will learn more about the speed formula and its applications.

What is the Speed Formula?

Let's move further and explore more about the speed formula in this section. Different units can be used to express speed, like m/s, km/hr, miles/hr, etc. The dimensional formula of speed is [LT^-1]. Speed is a measure of how fast a body is moving. The formula for the speed of a given body can be expressed as,

Formula for Speed

Speed = Distance ÷ Time

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/Speed
Let'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 ÷ Time
Speed = 3600 ÷ (30 × 60) = 2

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

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 second
Using 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 second
Using 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 [Speed = Distance ÷ Time]
Distance = 40 kilometers
Time = 2 hours
Speed = (40 ÷ 2) km/hr
= 20 kilometers per hour

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