Question

You pull a your friend along in a sled (combined mass is 65 kg), by pulling the rope at an upward angle of 20 degrees with respect to the ground with enough force to keep the sled moving at a constant velocity of <3,0, 0> m/s. The coefficient of kinetic friction between the ground and the sled is 0.15. (a) Draw a force diagram for the friend/sled system. (b) Once you get to constant velocity, you pull the sled 15 m. What is the work done by friction on the sled? (c) What is the total work done on the sled? (d) What force ! F must you apply to the rope to keep the sled moving at constant velocity over this distance? (Note that I am asking for a vector!) (e) At this point, you stop pulling and let the sled come to rest. Draw the force diagram for the sled/friend system after you stop pulling. (f) Use the work energy theorem to find the distance the sled travels before coming to rest.

Answer 1

Soch: m=65k9,-20, V= 3 m 13 tie = 0.15 TSinzo N I 20 STC0520* du Img 160 M tigar 0.15*6544-86 & Since, Sled is moving with const vel. So, a=0 . dic = Tosco (N=mg-T 816 20") Me N=T0126 0.15 (65*9.8-T Sin 20) T60120 95.55-0.651T = 0.qut 0.991 T = 95.55 - [T = 96.450 N= mg-T8120 N=65x9,8- 96.45 Sin 20'= 604.OIN HINd=-0.15 x 60401x15 2 d) Cood by friction, egoeruese me voy = 1359.025 Total wood on sled, W=0 T-96.45N F 96.45 Lov 20° î +96.45 3m 2009 7- 90.63 î + 32.995 |6J 1 mv2_sr mg d = 0 d=v2 - 9 | 24kg - 2x0.559978 Id= 3.061 m ving