I am going to go ahead with the answer to case 1. Really, this one should be easy (it wasn't a trick). The pulling force is to the left, the bike rolls to the left. No surprises here (hopefully).

In a new video, a team of robo-puppers pulls a truck as if it were a sled. Here's how to estimate these SpotMinis' pulling force and the friction involved.

The PF8 Pull Force Estimator allows users to estimate in advance the pulling force required for cable pulling jobs. The estimator consists of an Excel-based calculator that can be downloaded to a PC ...