Answer:
(1) 3.0 dm
Explanation:
Due to the law of conservation of energy, the initial gravitational potential energy of the object will be all converted into elastic potential energy of the spring as the object hits the spring:

where
m = 4.0 kg is the mass of the object
g = 9.8 m/s^2 is the acceleration due to gravity
h = 1.0 m is the initial height of the object
k = 850 N/m is the spring constant
x is the compression of the spring
Solving the equation for x, we find:
