Here is a transcript of the question shown in your image: --- **Question 4 (10 pts)** --- ### A2 [10 pts] Solve this problem on your own paper or tablet and submit your full written solutions in the File Upload question of this exam, as part of a single PDF file. In the event you are unable to submit a single PDF file of your full solutions, you may enter your final answers (with units where applicable) in the next question as a backup. However, full marks will only be awarded for full written solutions. Your friend (mass of 60 kg) is tired of carrying groceries in a backpack and decides instead on a new strategy: pull a cargo trailer (15 kg) attached to their bike (mass of 8 kg) with a lightweight rope. The bike has new tires that are firmly inflated, so rolling friction can be neglected. On the other hand, the tires on the trailer are quite soft and it has a rolling friction force of 17 N exerted on it. After loading the trailer with 15 kg of groceries, your friend uniformly increases their speed from rest to 15 km/hr in 5 seconds (without slipping the tire on the ground). During this time, the rope is taut and is at a constant angle of θ = 30° above the horizontal (as shown below). --- #### (a) [3 pts] Draw two free-body diagrams: one for the trailer and another for the bike. Clearly identify and label all forces, the angle θ and your coordinate system. *Note that you don’t have to make your force vectors exactly to scale, but make sure that their relative lengths make sense given the above information.* #### (b) [3 pts] While the bike was accelerating, what was the magnitude of the force of the ground on the bike that propelled it forward? #### (c) [1 pt] What was the magnitude of the force of the rope on the trailer? #### (d) [2 pts] What is the coefficient of rolling friction between the ground and the trailer’s tires? #### (e) [1 pt] Briefly explain using Newton laws what will happen when your friend brakes at the next stop sign. Was your friend’s new strategy a good idea? Keep your answer to 2-3 sentences max. --- If you need help with any of these parts, let me know which one!