Question

Josh pulls a sled with a force of 100-N at an angle 30° above horizontal axis. The total mass of the sled and Josh’s sister is 60.0-kg. The friction coefficient between the surface and the sled:static= 0.160; kinetic= 0.100

a) Determine if Josh can move the sled.
b) If the sled can be moved, determine the acceleration of the sled.

Answer 1

static Horizontal pull force
= 100 cos 30 = 86.6 N

normal force = 60*9.81 - 100 sin 30
= 539 N

static friction force = .16*539 = 86.2 N

so it does start moving

kinetic friction force = .1*539 = 53.9 N
so net force = 86.6-53.9 = 32.7 N

a = F/m = 32.7/60 = 0.545 m/s^2