The discussion focuses on calculating the tension between a car and a trailer, emphasizing the importance of free body diagrams and force balance equations. Participants highlighted the necessity of including friction forces acting on the car while clarifying that friction is not applicable to the trailer since its tires are idling. Key concepts discussed include Newton's second law (f = m * a) and the correct representation of forces in free body diagrams. Ultimately, the participants reached a solution by accurately identifying the forces acting on both the car and the trailer.
PREREQUISITESStudents studying physics, particularly those focusing on mechanics, as well as educators and anyone interested in understanding the dynamics between vehicles and trailers.
It is unnecessary to include a friction arrow for the trailer because its tires are not driven; they are just idling. But including a friction arrow for the force the road exerts on the car is important. Which direction do you think this arrow is pointing?Thomas Hochkins said:
A car engine is not a jet engine. If there were no friction between tyres and road, would the car go?Thomas Hochkins said:
This is not correct. As haruspex was alluding to in the previous post, the frictional force exerted by the road on the car tires is pointing forwards, in the direction that the car is moving. The tires are driven by the car engine, and they are pushing backwards on the road surface. The road surface, in turn, is pushing forward on the car. This is where haruspex was saying that the forward arrow should go.Thomas Hochkins said: