5. A bicyclist is finishing her repair of a flat tire when a friend rides by at a constant velocity of 3.5 m/s. Three seconds later, the bicyclist hops on her bike and accelerates at 3.6 m/s² until she
catches her friend.
a. How much time does it take until she catches her friend?
b. How far has she traveled in this time?
c. What is her speed when she catches up?

a) t = 3.6 s

b) d = 23 m

c) v = 13 m/s

Explanation:

Let t be the time the accelerating rider rides

the distance she travels is

d = ½3.6t²

the distance for the other cyclist is

d =3.5(t + 3)

½3.6t² = 3.5(t + 3)

1.8t² - 3.5t - 10.5 = 0

quadratic formula, positive answer

t = (3.5 + √(3.5² - 4(1.8)(-10.5))) / (2(1.8))

t = 3.575786...

d = ½(3.6)(3.575786²) = 23.015...

v = 3.6(3.575786) = 12.8728...