MHB Finding Distance with Constant Speed: Solving for m and b

AI Thread Summary
John's distance from the motion sensor can be modeled by the equation d = mt + b, where d is distance in meters and t is time in seconds. Given the data points, the slope (m) can be calculated as 0.75 m/s, indicating John's constant speed, while the y-intercept (b) is 1.75 m, representing the initial distance from the sensor when t = 0. By substituting t = 5 into the equation, it can be determined that John will be 5.25 meters from the sensor after 5 seconds. The discussion emphasizes the relationship between time and distance, showcasing linear motion. This analysis illustrates how to derive a linear equation from real-world movement data.
Abdullah Qureshi
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John is walking at a constant speed in front of a motion sensor. After 1 s, she is 2.5m from the sensor, 2 s later, she is 4 m from the sensor.
a) Find an equation of in the form d=mt+b
b) Determine the slope and d intercept and explain what they mean
c) How far will John be from the sensor 5s after he begins walking?
 
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distance from the sensor is a function of time in seconds

$d(1) = 2.5 \, m$
$d(1+2) = d(3) = 4 \, m$

slope, $m = \dfrac{\Delta d}{\Delta t} \, m/s$

see what you can do from here ...
 
Equivalently, since you are told that d= mt+ b, when t= 1, d= 2.5, so 2.5= m+ b and when m= 3, d= 4 so 4= 3m+ b.

Solve the two equations, m+ b= 2.5 and 3m+ b= 4, for m and b. I suggest you subtract the first equation from the second to eliminate b.
 
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