$2.$ A sled is pulled horizontally across the snow at constant velocity. The pulling force is $40$ N$.$

a$.$ What is the Kinetic Frictional Force on the Sled?$(40$ N$)$

b$.$ If the weight of the sled is $200$ N$,$ what is the co$$efficient of Kinetic Friction $($k$)$ between

the sled and snow?$(0\mathrm{.}20)$

c$.$ If $30$ kg of wood is placed in the sled, what pulling force is needed to move the

sled at constant velocity?$(98\mathrm{.}8$ N$)$