1. The problem statement, all variables and given/known data Hey everyone, I'm new to this forum so Let me first introduce myself to the community. I am a grade 11 High school student from Toronto, Canada. I have joined this forum in hopes of gaining access to support whenever i need help on my Physics homework. I have a question.. So there is a Cart that weights 0.521 Kg and its on a frictionless track and its attached to a string that attaches it to a weight of an UNKNOWN MASS through a frictionless pulley. The Track is 1 Meter long, How much mass (UNKNOWN MASS) would be required to pull the cart down to the end of the track (total distance: 1 meter) in 2 seconds? The cart travels at a constant velocity so there is no acceleration. This picture simplifies the question. http://i.imgur.com/083cve3.jpg?1 2. Relevant equations The Big 5 Equations. 3. The attempt at a solution I have figured that I am solving for the Applied Force. I'm new to Physics so I am understandably stuck.