Answer:
a)
, b) 
Explanation:
a) The Hooke's law states that spring force is directly proportional to change in length. That is to say:

In this case, the force is equal to the weight of the object:



The spring constant is:



b) The length of the spring is:




Answer:
x ’= 368.61 m, y ’= 258.11 m
Explanation:
To solve this problem we must find the projections of the point on the new vectors of the rotated system θ = 35º
x’= R cos 35
y’= R sin 35
The modulus vector can be found using the Pythagorean theorem
R² = x² + y²
R = 450 m
we calculate
x ’= 450 cos 35
x ’= 368.61 m
y ’= 450 sin 35
y ’= 258.11 m
The car is the heaviest object there and mass is proportional to force, meaning the heavier it is the bigger the force should be in order to move it.