The sled in Figure 4.2 is stuck in the snow. A child pulls on the rope and finds that the sled just barely begins to move when he pulls with a force of 25 N, with the rope at an angle of 30° with respect to the horizontal.

(a) Sketch the sled and all the forces acting on it. Also choose a coordinate system. 

(b) Determine the components of all the forces on the sled along the coordinate axes. 

(c) Write the conditions for static equilibrium along your two coordinate directions. 

(d) If the sled has a mass of 12 kg, what is the coefficient of friction between the sled and the snow? 

(e) Is this the coefficient of static friction or the coefficient of kinetic friction? 

(f) If the child continues to pull on the sled and it has an acceleration of 0.30 m/s², find the coefficient of kinetic friction between the sled and the snow.

Figure 4.2

Transcribed Image Text:

Fpull = T sin 0 T T, = T sin A Ffriction Friction Friction T= T cos 0 T = T cos 0 Fgrav grav mg Components of the tension Free-body diagram with all forces resolved into Free-body diagram force Ť components along x and y