Question

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

Answer 1

Answer:0.21

Explanation:

Given

mass of turtle $m=12 kg$

velocity of Truck $v=55 mi/h\approx 24.58 m/s$

time taken to stop $t=12 s$

using $v=u+at$

where v=final velocity

u=initial velocity

a=acceleration

t=time

$0=24.58+a\cdot 12$

$a=-\frac{24.58}{12}$

$a=-2.04 m/s^2$

therefore 2.04 is the deceleration experienced by turtle which is countered by frictional force

$a=\mu g$  ,where $\mu =$coefficient of friction

$2.04=\mu \times 9.8$

$\mu =0.209\approx 0.21$