From laws of motion:

Where S is the distance/displacement (as you would call it) which is unknown
v = final velocity which is 0m/s (this is because the car stops)
u = initial velocity which is 36m/s (from the data given)
t = time taken for the distance to be covered and it is 6s
Substitute the values, hence:


But this is merely the distance he travelled in the 6 seconds he was trying to stop the car.
Therefore, the distance between the car and the cows = 160-108
Distance = 52m
The elastic potential energy stored in a spring is given by:

where k is the spring constant, and x=0.5 is the compression of the spring. Re-arranging the formula and using E=5 J, we find the spring constant:

Answer: 39.5 N
Explanation:
2 x force x static friction coefficient = weight (weight=2μsF)
force = ?
static friction coefficient = 0.416
weight = 32.9N
substituting the values above into the equation we get
2 x F x 0.416 = 32.9
F = 32.9 / (2 x 0.416)
F = 39.5N