A girl coats down a hill on a sled

[chenny]

reaching level ground at the bottom with a speed of 7.0 m/s. the coefficient of kinetic friction between the sled's runners and the hard, icy snow is 0.050, and the girl and sleed together weight 645 N. how far does the sled travel on the ground level before coming to rest?

 

[geoffjb]

reaching level ground at the bottom with a speed of 7.0 m/s. the coefficient of kinetic friction between the sled's runners and the hard, icy snow is 0.050, and the girl and sleed together weight 645 N. how far does the sled travel on the ground level before coming to rest?

What have you tried so far? Where are you running into difficulty?

 

[chenny]

i just took one look at the problem and my mind went blank. i totally do not know how to start it.

 

[geoffjb]

i just took one look at the problem and my mind went blank. i totally do not know how to start it.

Draw a free body diagram. What are the forces acting on the sled?

Remember to break everything up into x- and y-components.

$$v_{f}^{2}=v_{i}^{2}+2ad$$

$$v_{f}=v_{i}+at$$

$$x_{f}=x_{i}+v_{0}t+\frac{1}{2}at^{2}$$

$$F_{k}=\mu_{k}N$$

$$F=ma$$

$$w=mg$$