In: Civil Engineering
Consider three vehicles running on a circular track of circumference 2 km. Vehicle A travels at a constant speed of 30 km/h, vehicle B travels at 60 km/h and vehicle C travels at 90 km/hr. Calculate the ratio of space mean speed over time mean speed.
Space mean speed is defined as the average of speed measurements at a particular instant of time of all vehicles over a particular instant of time of all vehicles over a particular stretch of highway.
The formula for Space mean speed is,
Where,
D is the length of road considered
ti is the time taken by the ith vehicle to cross the considered road length.
n is the number of vehicles observed
Here, n = 3
D = 2 km
V1 = 30 km/hr
V2 = 60 km/hr
V2 = 90 km/hr
Therefore the equation for space mean speed becomes,
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Time mean speed is defined as the average of the speed measurements at one point in space of all vehicles passing over a period of time.
The equation for Time mean speed is,
Vi = Velocity of ith vehicle
n = number of vehicles
Here, n = 3
V1 = 30 km/hr
V2 = 60 km/hr
V2 = 90 km/hr
So the equation becomes,
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The ratio of space mean speed over time mean speed is,