Question

Suppose the vector describing the location of a car moving in a straight line is given by d=<15t, -36t>, where the distance is in miles and the time 't' is in hours. To the nearest minute, how long will it take for the car to move 24 miles?

Answer 1

Apply the distance formula
$d= \sqrt{ (x_2 - x_1)^2 +(y_2-y_1)^2}$

except if you use the starting point of (0,0), its essentially an application of pythagorean theorem

x2 would be 15*t
y2 would be -36*t

and d would be 24

writing it all out would be
24^2= (15t)^2 + (-36t)^2

in which case, just expand, and solve for t

any questions?