BRAVO! You're right!

Disney's Rockin' Roller Coaster is catapulted from 0 to 60 mi/h in 2.8 s. What is its acceleration?

We know the speed in mi/h and we know the time in s. Life is far easier if the times involved have the same units. Life is somewhat easier if we stay with a single set of units. Therefore, we will change

everythingto SI units:v

_{i}= 0v = 60

^{mi}/_{h}[^{1.61 km}/_{mi}] [^{h}/_{60 min}] [^{min}/_{60 s}] [^{1 000 m}/_{km}]v = 26.8 m/s

Nowwe are ready to "plug into" our equation,v = v

_{i}+ a t26.8 m/s = 0 + a (2.8 s)

a =

^{26.8 m/s}/_{2.8 s}a = 9.6 m/s

^{2}Notice that that is

nearlyequal to the acceleration of gravity!

(c) 2001, Doug Davis; all rights reserved.