A problem representation is a cognitive structure created by the solver in correspondence to the problem. Sketching representative diagrams in the domain of physics encourages a problem solving strategy that starts from 'envisionment' by which one internally simulates the physical events and predicts outcomes. Research studies also show that sketching representative diagrams improves learner's performance in solving physics problems. The pedagogic benefits of sketching representations on paper make this traditional learning strategy remain pivotal and worthwhile to be preserved and integrated into the current digital learning landscape. In this paper, I describe AR Physics, an Augmented Reality based application that intends to facilitate one's learning of physics concepts about objects' linear motion. It affords the verified physics learning strategy of sketching representative diagrams on paper, and explores the capability of Augmented Reality in enhancing visual conceptions. The application converts the diagrams drawn on paper into virtual representations displayed on a tablet screen. As such learners can create physics simulation based on the diagrams and test their "envisionment" for the diagrams. Users' interaction with AR Physics consists of three steps: 1) sketching a diagram on paper; 2) capturing the sketch with a tablet camera to generate a virtual duplication of the diagram on the tablet screen, and 3) placing a physics object and configuring relevant parameters through the application interface to construct a physics simulation. A user study about the efficiency and usability of AR Physics was performed with 12 college students. The students interacted with the application, and completed three tasks relevant to the learning material. They were given eight questions afterwards to examine their post-learning outcome. The same questions were also given prior to the use of the application in order to compare with the post results. System Usability Scale (SUS) was adopted to assess the application's usability and interviews were conducted to collect subjects' opinions about Augmented Reality in general. The results of the study demonstrate that the application can effectively facilitate subjects' understanding the target physics concepts. The overall satisfaction with the application's usability was disclosed by the SUS score. Finally subjects expressed that they gained a clearer idea about Augmented Reality through the use of the application.