3) Eric goes ice fishing and pulls a sled behind him so the sled moves at constant speed. The rope exerts a constant force of 60 N at an angle of 56 above the horizontal. The mass of the sled (with all the cargo) is 40 kg. Consider friction between the sled and the surface of the frozen lake. a) (5p) Draw a free-body diagram for the sled (into the coordinate system provided). Fuet = 0 b) (5p) Calculate the normal force from the ground onto the sled. OT 4) (4p) Three friends are sliding on a toboggan down a slope with a constant angle of 20. Their combined weight including the toboggan is 220N. The friction force is 56 N. Calculate the coefficient of kinetic friction. (a) The situation equipementa (b) Free-body diagram for toboggan Y fk In W COS w sin 2 Newton's Second Law: Fix F2x () () (+ F2y Fner = ma = Weight: F=mg g=9.81- 8 S ax +=m Fix + F2x+F3x+... = Fly+F2y+F3y+... = 1 ... = may and max Friction: kinetic fk = 14k FN static fmax = s FN 0fs fma Vectors |V|=v + buang w hypotenuse V "SOH CAH TOA" Vy 90 opposite Vx adjacent Show your work! In order to get full credit, you need to document your problem-solving steps (e.g. equations, arguments, calculations) so a reader can follow how you got your result. Use the correct units in your answers or you will lose points! Make sure you have set your calculator to degrees. Self-test: cos 56= 0.559 and sin 56= 0.829 1a) (2p) Add the following two vectors: -5 *-(7)-(0)-(1)~ R = + = 1b) (2p) Calculate the magnitude of vector R 2) (4p) Using the graphical method of vector addition, construct the vector sum of the three vectors shown. A 20 10 13 B Clearly indicate the direction of each vector that you draw and label each vector. You get points for showing the construction; the result alone is not enough. -20 -10 10 20