Homework # 26 Friction Handout Problems: 1. What will happen to the coefficient of static friction between two objects if (a) the normal force between the objects is doubled? (b) the surfaces are lubricated with grease? 2. A 40.-N object requires 5.0 N to start moving over a horizontal surface. What is the coefficient of static friction? 3. Once the object of the last question is moving how much force will be needed to keep it moving: more than 5 N, less than 5 N, or exactly 5 N? Explain. 4. A 50. N horizontal force is needed to keep an object weighing 500 N moving at a constant velocity of 2.0 m/s east across a horizontal surface. What is the magnitude and direction of the frictional force acting on the object? 5. The coefficient of kinetic friction between a 780. N crate and a level warehouse floor is 0.200. Calculate the magnitude of the horizontal force required to move the crate across the floor at constant speed. 6. If a 30-N force is required to accelerate a 2-kg object at 10 m/s over a level floor, then what is the magnitude of the frictional force acting on the object