Exercises 23, 24, 25, 26, and 27 describe a situation. For each, identify all forces acting on the object and draw a free-body diagram of the object. Your physics textbook is sliding across the table.

Video transcript

Hey, everyone in this problem, we have a block of wood sliding across the floor and we're asked to use the scenario to identify the forces acting on the block of wood and draw a free body diagram. The answer choices were given, show free body diagrams with each of them having different forces included. In option A, we have the force of gravity, the normal horse and kinetic friction. An answer B we have the force of gravity and kinetic friction. An option C we have kinetic friction moving forward and then option D we have the force of gravity in the normal course. Let's go back up to this statement with the scenario and draw this out ourselves. We have our free body diagram. So we draw our block in the middle of a dot Now this block is on a, on the floor sliding across the floor, it's on a surface. And we know that we always have a normal force pointing perpendicular to the surface. So we know we have the normal horse pointing straight up. In this case, our block has some mass as well. Okay. So we have the weight of that object or the force of gravity acting on that object that's going to act downwards. So we have our normal force pointing upwards, our force of gravity or the weight if you'd like to call it acting downwards. And this blog is sliding across the floor. We're not told that the floor is frictionless. So we're going to assume that there is friction as there would be with a normal floor if we have our block moving to the right and the force of friction is going to back to the left to oppose the motion. Okay. So we have a friction force f and what will our net force be? Well, the normal force and the weight, those will cancel each other out equal in magnitude but opposite in sign. And so we have no net force in the Y direction and in the X direction, we have just this kinetic friction force acting to the left. And so our net force is going to be to the left. Now, if we compare these with the answer choices were given and we see that this matches with answer choice. We have the normal force pointing up the force of gravity or the weight pointing downwards, the kinetic friction, opposing the motion, pointing to the left and that net force directed to the left. So the correct answer is answer choice. A that's it for this one. Thanks everyone for watching. See you in the next video.