Question

2. You an three friends built a makeshift bobsled for a on grass bobsled race. Due to the conditions, your main goal is to at least get to the goal which is x -75 m horizontally from the starting line and at the bottom of a θ = 5° hill. You are given a running start region on flat ground for d 25 m. The entire course is on grass which give a coefficient of static friction of H-0.40. What is the minimum required average force F you and your friends need to push on the running start area ifthe bobsled weighs m -15 kg and the combined weight of you and your friends is M 350 kg if you want to reach the finish ine? (10 points) [Note: The answer is somewhat large.] Start Line Finish Line

need help understanding this problem

Answer 1

The work done by gravity and applied force is equal to work done by frictional force The frictional force at horizontal place is, (04)(15+350)(9.8) -1430.8 N The frictional force at incline is cOS -0.4(15+350) (9.8) (cos 5) - 1425.35 N Here we consider only incline frictional force. The applied force at start line needs to be calculated. The work done by frictional from start line to finish line is cos θ 75 cos 5 -(1425.35) -1.07x105 J This work done is equal to work done by gravity and work done by applied force Now W -W -1.07 x105 r-(1.07x105 )(c5 )-(m+M)gsín θ 75 - (1.07x10 -(15+350) (9.8) (sin5) 1 1 13.59N 1114 N