"Sufficient level" problems often require 2–3 steps of calculation, such as finding the mass of an object given the friction force and coefficient, or determining the coefficient of friction from experimental data. Task : A wooden crate with a mass of
Note: For constant speed, the pulling force must equal the friction force. Task : To pull a sled at a constant speed, a force of is applied. Find the coefficient of friction. Solution : 4. Key Takeaways for Kirik's Methodology fizika 7 klass kirik sila treniia dostatochnyi uroven
: For sliding friction, the force is proportional to the normal force (weight on a horizontal surface): Ffr=μ⋅Ncap F sub f r end-sub equals mu center dot cap N Ffrcap F sub f r end-sub is the friction force (Newtons, "Sufficient level" problems often require 2–3 steps of
: Occurs when a body rolls (e.g., a wheel); it is usually much smaller than sliding friction for the same materials. 3. Example Problems (Sufficient Level) Find the coefficient of friction
: Prevents an object from starting its motion. It is equal in magnitude to the applied pulling force until the maximum threshold is reached.
