force is given by F, = F When the surface becomes an inclined plane, the normal force changes and when the normal force changes, so does the friction. The Ramp In this lab, you will change the angle of an inclined plane and observe how weight is resolved into its components (Fn and F//) using the basic trig functions. Procedure: Play with the Sims > Physics >Motion > The Ramp Run Novel Be sure to stay in the Introduction part of the simulation. More features will be used later when we investigate energy. Start by playing with the cabinet. Move the cabinet up and down the ramp by dragging it with your mouse. Horizontal plane Move the ramp to an angle of zero (horizontal) and draw a free body diagram of the cabinet here: 1. On a horizontal plane, the normal force is Perpendicular to the weight. 2. The cabinet has a mass of 100kg. It therefore has a normal force of -100N N and a friction force (on the horizontal plane) of 2.22 1 =0.30 Inclined plane | Reset | the ramp and draw a free body diagram of the cabinet in the box here: 3. The force down the plane and normal force are components of Force diagrams 4. Before we add an applied force on the ramp, there is a force of Gravity that acts against the force down the plane( Force parallel). 5. When we apply a force to get the cabinet moving, the friction force acts in the Go! Opposite direction as movement of the cabinet. 6. Slowly increase angle (0.1 degrees at a time) of the ramp until the cabinet starts to move on its own. What angle is this? _acute Normal 7. At this point, the force down the plane is Same than the force of friction. 8. Since the ramp is now at an angle, the normal force is_ Less than the weight. Friction Total 9. At the angle above, the normal force equals Cos N. (hint: what trig function?) 10. At the angle above, the force down the plane equals Sin N. (trig function?) -Weight 1 1. Using the formula for friction above, the force of friction is 0.56 N. 12. If the plane-cabinet were frictionless, what angle would be required for the cabinet to move? acute If the plane cabinet were frictionless for the cabinet to move an acute angle would be required an acute angle is An inclined 13. Why? plane which allows for this frictionless slide with help of gravity and inclined plane the cabinet will move downward g = 9.8m/s2 Calculate first, then test each object in the table below with the simulation on a horizontal plane. Object Mass Weight Normal Force u, Coef of Friction Friction Force to Overcome Dog 0.10 15g -495N 147N 14.7N Crate 100kg 222N 980N 0.70 586N Piano 225kg 1125N 2205N 0.40 882N 175kg Refrigerator -680N 1715 N 0.50 857.5N
