dissipation is the answer ;(
Answer:

Explanation:
F = Force on the sled = 63 N
m = Mass of sled = 28.7 kg
= Coefficient of kinetic friction = 0.169
g = Acceleration due to gravity = 
The force balance of the system is given by

The acceleration of the sled is
.
Answer:
Explanation:
Both are contact forces arising at the interface between two bodies. In the fluid this interface might be irregular, and it completely surrounds a submerged object. For a solid it is usually a single flat surface - but it can be a collection of surfaces, which do not need to be flat or regular, and which can surround the object
Upthrust occurs at a fluid-solid interface whereas normal reaction occurs at a solid-solid surface. However, it is possible to generate the same fluid-like phenomenon of upthrust by immersing a solid object in sand or small beads and agitating them to simulate the pressure of atoms. With