1) A 27 kg chair initially at rest on a horizontal floor requires a 373 N horizontal force to set
it in motion. Once the chair is in motion, a 344 N horizontal force keeps it moving at a constant velocity.
The acceleration of gravity is 9.81 m/s^2
a) What is the coefficient of static friction
between the chair and the floor?

b) What is the coefficient of kinetic friction
between the chair and the floor?


2) Once a 21 kg crate is in motion on a horizontal floor, a horizontal force of 55 N keeps the crate
moving with a constant velocity.The acceleration of gravity is 9.81 m/s^2.
What is µk, the coefficient of kinetic friction, between the crate and the floor?

THANK YOU

Friction force is modelled as:



where F is force applied parallel to the surface the obkect is istting on and N is the normal foprce between the object and the surface. In this case N is equal to the object's weigt, so you have



If you use the coefficient of static friction in this formula it yields a value for F where the object first starts moving from rest. If you use the coeffcient of kinetic friction for you get the force required to keep it moving at a constant velocity. You have been given enough informatio to determine these coefficients of friction - post back with your attempt at solving these problems and we'll help if you get stuck.