Answer:
The equation for the object's displacement is 
Explanation:
Given:
m = 16 lb
δ = 3 in
The stiffness is:

The angular speed is:

The damping force is:

Where
FD = 20 lb
u = 4 ft/s = 48 in/s
Replacing:

The critical damping is equal:

Like cc>c the system is undamped
The equilibrium expression is:

Assume the snow is uniform, and horizontal.
Given:
coefficient of kinetic friction = 0.10 = muK
weight of sled = 48 N
weight of rider = 660 N
normal force on of sled with rider = 48+660 N = 708 N = N
Force required to maintain a uniform speed
= coefficient of kinetic friction * normal force
= muK * N
= 0.10 * 708 N
=70.8 N
Note: it takes more than 70.8 N to start the sled in motion, because static friction is in general greater than kinetic friction.
Volume= Length X width X height.
Plug in the values for each and solve for the volume.
V= (L)(W)(H)
V=(4cm)(5cm)(10cm).
If the object is in equilibrium that means that the sum of the forces on it is zero and the net force is zero. If none of the forces changes then the object continues in constant uniform motion. That means constant speed in a straight line.