Average Speed Formula

The Average Speed of an object is a measure of the distance covered by that object in a set period of time. It is the distance covered, divided by time. Average speed has a magnitude, and is a scalar quantity

s_Avg = ΔD/Δt

D = distance, meters (m)

t = time,sec (s)

Δ = short form for 'the change'

ΔD = short form for 'the change in distance'

ΔD = D₁ + D₂ + D₃ + ...D_n

Δt = short form for 'the change in time'

Δt = t₁ + t₂ + t₃ + ... t_n

Average Speed Formula Questions:

1) A vehicle moves 500 m in 2.5 minutes. What is the average speed of the vehicle? The distance traveled is D = 500 m; the time it took to cover that distance is t = 2.5 minutes. 2.5 minutes x 60 sec/min = 150 seconds. Now use the formula.

s = D/t

s = 500 m /150 sec

s = 3.33 m/s

2) If you drive from your house in Denver to Colorado Springs, and drive 60 meters in the first hour, 45 meters in the 2nd hour, and 30 meters in the third hour, what is your average speed?

The distance ΔD traveled is D = 60 meters + 45 meters + 30 meters = 135 meters. The time Δt = 1 hr + 1 hr + 1 hr = 3 hrs x 60min/hr x 60 sec/min = 10800 seconds. Now use the formula for average speed.

s = ΔD/ Δt

s = 135 meters/10800 seconds

s = 0.0125 m/s