Question

as she climbs a hill, a cyclist slows down from 25mi/hr to 6mi/hr in 10 seconds. what is her deceleration? my answer is -1.9 is this correct or should it be a positive 1.9...am confused

Answer 1

Here is my mathematical approach
physics has nice formulas for this

v = at + c
when t = 0, v = 25
so 25 = 0+c
c = 25

then v = at + 25
when t = 10 , v = 6
6 = 10a + 25
10a = -19
a = -1.9

Whenever you see the word deceleration (things slow down) you can expect a negative result, just like for acceleration you can expect a positive answer.