Ch 05: Friction, Inclines, SystemsWorksheetSee all chapters
All Chapters
Ch 01: Units & Vectors
Ch 02: 1D Motion (Kinematics)
Ch 03: 2D Motion (Projectile Motion)
Ch 04: Intro to Forces (Dynamics)
Ch 05: Friction, Inclines, Systems
Ch 06: Centripetal Forces & Gravitation
Ch 07: Work & Energy
Ch 08: Conservation of Energy
Ch 09: Momentum & Impulse
Ch 10: Rotational Kinematics
Ch 11: Rotational Inertia & Energy
Ch 12: Torque & Rotational Dynamics
Ch 13: Rotational Equilibrium
Ch 14: Angular Momentum
Ch 15: Periodic Motion (NEW)
Ch 15: Periodic Motion (Oscillations)
Ch 16: Waves & Sound
Ch 17: Fluid Mechanics
Ch 18: Heat and Temperature
Ch 19: Kinetic Theory of Ideal Gasses
Ch 20: The First Law of Thermodynamics
Ch 21: The Second Law of Thermodynamics
Ch 22: Electric Force & Field; Gauss' Law
Ch 23: Electric Potential
Ch 24: Capacitors & Dielectrics
Ch 25: Resistors & DC Circuits
Ch 26: Magnetic Fields and Forces
Ch 27: Sources of Magnetic Field
Ch 28: Induction and Inductance
Ch 29: Alternating Current
Ch 30: Electromagnetic Waves
Ch 31: Geometric Optics
Ch 32: Wave Optics
Ch 34: Special Relativity
Ch 35: Particle-Wave Duality
Ch 36: Atomic Structure
Ch 37: Nuclear Physics
Ch 38: Quantum Mechanics

Concept #1: Static Friction & Equilibrium

Practice: The system below does not move. Find the minimum value that μ,S (between 8 kg block and table) can have.

Practice: A 15 kg block is initially at rest on a horizontal surface. The coefficients of friction between the block and the surface are 0.5 and 0.7. How hard must you push down the block to keep a 300 N force in the +x from moving it?

Additional Problems
Consider the figure below, graphing the force applied on a 200 kg box vs time. During the first 0.5 s on the graph, the box remains at rest, while during the remaining time on the graph, the box moves at a constant speed of 15 m/s. What is the maximum coefficient of kinetic friction during the motion of the box?
Consider the figure below, graphing the force applied on a 200 kg box vs time. During the first 0.5 s on the graph, the box remains at rest, while during the remaining time on the graph, the box moves at a constant speed of 15 m/s. Assume that the decrease in the coefficient of kinetic friction is due to changes in the surface the box moves across. How far across this surface does the box have to travel for the coefficient of kinetic friction to reach half its maximum value?
A 5 kg box sits atop a 20 kg box inside an elevator. If the elevator was accelerating upwards at 2 m/s2, how much force would you have to push the 20 kg box so that the 5 kg box falls off? Assume that there is no friction between the 20 kg box and the floor, and μs = 0.4 between the 5 kg and 10 kg box.
Consider the figure below, graphing the force applied on a 200 kg box vs time. During the first 0.5 s on the graph, the box remains at rest, while during the remaining time on the graph, the box moves at a constant speed of 15 m/s. What is the coefficient of static friction?
Consider the figure below, graphing the force applied on a 200 kg box vs time. During the first 0.5 s on the graph, the box remains at rest, while during the remaining time on the graph, the box moves at a constant speed of 15 m/s. At what time would the force of static friction be 0.5 kN?