You're using a rope to pull a sled at constant velocity across level snow, with coefficient of kinetic friction 0.050 between sled and the snow. The sled is loaded with physics books, giving a total mass of 39 kg

1. With what force should you pull with the rope horizontal?

2. Repeat for the rope at 30

Frictional force acting on the sled = μ mg, μ is coefficient of friction, m is mass of the load.

Frictional force acting on the sled =.05 x 39 x 9.8

= 19.11 N

So a horizontal force of 19.11 N is required to pull the rope so that it moves with uniform velocity. (net force zero so no acceleration)

When force acts at an angle of 30 degree

The horizontal component will be effective to pull the load and reaction force will be reduced

reaction force = mg - Fsin30

= 39 x 9.8 - F/2

frictional force =.05 (39 x 9.8 - F/2)

F cos 30 =.05 (39 x 9.8 - F/2)

.866 F +.025F = 19.11

F = 19.11 /.891

= 21.44 N.