A 12-kg turtle rests on the bed of a zookeeper’s truck, which is traveling down a country road at 55 mi/h. The zookeeper spots a deer in the road, and slows to a stop in 12 s. Assuming constant acceleration, what is the minimum coefficient of static friction between the turtle and the truck bed surface that is needed to prevent the turtle from sliding?

Answer 1

F=ma
mu(mg)=ma
for a, change 55mi/hr to m/s
a=changevelocity/timeinseconds
solve for mu.

Answer 2

so i change 55m/hr to 11m/720s. to solve for mu i times that by 12? then i get 11m/60s??

Answer 3

Good lord.
Put this int he google search window:
55miles/hr in m/s
Then use that (about 24m/s)

mu*g=(24-0)/12
mu= 2/9.8 about .2