An 56 kg sled is being pulled across the snow, at constant speed, by a horizontal force of 15 n, find the coefficient of kinetic friction, uk between the snow and sled.

The coefficient of  kinetic friction = 0.026  

Explanation:

An 56 kg sled is being pulled across the snow, at constant speed,by a horizontal force of 15 N.

Here we have to note that the weight is pulled at a constant speed . This means that the net force acting on the weight is zero.

The external force acting on the body is in the forward direction and the friction acts in the backward direction.

Friction increases as the mass of the body increases.

Friction =

We now equate this to the external force of 15 N.

15 =

=

= 0.026

The coefficient of  kinetic friction = 0.026  

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

i don't understand. explain it clearly