# Average Speed Formula

The average speed is the total distance travelled by the object in the particular time interval.

The average speed is a scalar quantity. It is represented by the magnitude and does not have direction.

Average Speed Formula

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

The average speed equation is articulated as:

$\inline \dpi{100} S_{avg} =$ Total Distance travelled/Total Time taken ………… (1)

${S_{AVG}}=&space;\frac{D_{total}}{T_{total}}\,&space;..........(2)$

Equation (2) is the formula for an average speed of an object moving at a varying speed.

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:

Given:

Total distance covered by the runner = 1000 meters

Total time taken =1minute 30 sec

= 90 sec
So, applying the formula for the average speed
we have,

$\inline \dpi{100} S_{avg} =$ 1000/90

$\inline \dpi{100} S_{avg} =$ 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?

D1 = 40 * 2 = 80 miles

D2 = 30 * 2 = 60 miles

Total distance D= D1+D2

D = 80 + 60

D = 140 miles

Average speed $\inline \dpi{100} S_{avg} =$ Total Distance travelled/Total Time taken

= 140/4

$\inline \dpi{100} S_{avg} =$  35 m/s