Transcript Document
Fri Sep 27 Announcements Attendance Homework Warm-up Interaction Forces FBD & Ramps Homework WS Interactive Forces WS FBD & Ramps Warm-up You are sitting in your 1050 kg car at a stoplight. When the light turns green you hit the gas. It takes you 10 s to reach a speed of 30 m/s. What is your acceleration? What is your force? What have we studied so far? GP 1 Converting Units Scientific Notation SOHCAHTOA Vectors Speed Velocity Acceleration 1D Kinematics GP 2 Force FBD Friction Interaction forces Newton’s 3rd law Two 5 kg blocks are sitting next to each other on a table. If you push one block into the other with a force of 50 N, what do the free body diagrams look like and what is the total acceleration? Strings have a force called tension. Strings do not add to force, it only changes the direction. A 10 kg block is hanging from a string. What does the free body diagram look like and what is the tension in the string? A 5 kg block is hanging from a 10 kg block that is also attached to a string. What are the tensions in the two strings? A 10 kg block is hanging from a 15 kg block that is also attached to a string. What are the tensions in the two strings? Normal force Think about what a scale would say. The water bottle has a mass of 10 kg. What is the normal force? A string is attached to the water bottle and is lifted with a force of 5 N, what is the new normal force? If a force of 10 N is pushing down on the bottle, what is the total normal force? Two books have a mass of 7 kg and 15 kg. If they are stacked on top of each other, what do the free body diagrams look like and what are all the forces? Two books have a mass of 3 kg and 5 kg. If they are stacked on top of each other, what do the free body diagrams look like and what are all the forces? A 450 kg horse trailer is attached to a 1050 kg truck with a chain. If the truck and trailer are accelerating at 3 m/s2, what are the forces on the trailer and truck? A 750 kg glider is attached to a 13500 kg plane with a cable. If the plane and glider are accelerating at 5 m/s2, what are the forces? Now we are going to talk about ramps What are the forces acting on the block? 1) Draw the FBD diagram for a 10 kg block on a 30o ramp. a. What is the force of gravity down the ramp? b. What is the normal force? c. What is the acceleration of the block down the ramp? d. What is the final speed of the block if the ramp is 2 m long? 2) Draw the FBD diagram for a 15 kg block on a 60o ramp. a. What is the force of gravity down the ramp? b. What is the normal force? c. What is the acceleration of the block down the ramp? d. What is the final speed of the block if the ramp is 5 m long?