Aman is pulling a 13-kg sled across a flat, snowy surface. he holds the handle of the sled at a 30° angle with the ground.
what is the minimum pulling force (f) to the nearest newton that the man must exert to keep the sled moving? (use the following constants: coefficient of sliding friction = 0.15; acceleration due to gravity = 9.8 m/s2, cos 30 = 0.87.)

a. 9.5 nb. 20 nc. 19 nd. 22 ne. 130 n