In: Physics
Calculate the maximum acceleration of a car with four wheel drive that is heading up a 8° slope (one that makes an angle of 8° with the horizontal) under the following road conditions. Assume that the static coefficient of friction is involved--that is, the tires are not allowed to slip during the acceleration.
(a) on dry concrete
________m/s2
(b) on wet concrete
_________ m/s2
(c) on ice, assuming that µs = 0.100, the same as for
shoes on ice
_________m/s2
coefficient of friction
dry concrete 
on wet concrete 
on ice 

where:
static friction force.
Normal
force
car
weight
horizontal component of weight


vertical component of the weight


Applying Newton's second law in the x axis

but the sum of the forces on the horizontal axis is equal to

combining equations

remember
and
now
is necessary to obtain expression N
not
accelerate vertically
but also

combining

replacing
expression of N
substituting in
is obtained

simplifying m

organizing

if
acceleration of gravity

the equation is evaluated for each coefficient of friction
(a) on dry concrete



evaluated numerically

(b) on wet concrete



evaluated numerically

(c) on ice



evaluated numerically
the
negative indicates that the car can not speed upward