1. Start the Computer Simulation by clicking the APP (check the APP under the Group Discussion) 2. Click Introduction, setup as following: Object: Small Crate (100kg) Friction: Wood (us = 0.5, uk = 0.3) Object Position: 5m Angle: Group 1 280 Group 2 320 Group 3 350 Group 4 380 Group 5 40 3. Click "Play", adjust the applied force to find minimum force to push object up. 4. Adjust the applied force to find maximum force which still allow the object to slide down. 5. Repeated steps 3 and 4 by change the object to Textbook