# Constant Velocity or Acceleration

1. Nov 4, 2013

### Noobstorm

1. The problem statement, all variables and given/known data
a 3 kg block is placed on an incline of 37 degrees with respect to the horizontal. The coefficient of static friction is 0.333, and the coefficient of kinetic friction is 0.167. What type of motion, constant or acceleration, will be observed?

2. Relevant equations
μ = Friction / Normal
Force = Mass * Acceleration

3. The attempt at a solution

3(9.8) = 29.4
Fgx = 29.4sin37

.333 = f / 29.4sin37
f (static friction) = 5.89188944

.167 = f / 29.4sin37
f (kinetic friction) = 2.954791401

I really have no idea how to determine whether it's moving at an acceleration or constant velocity. Any help would be appreciated :)

Last edited: Nov 4, 2013
2. Nov 4, 2013

### voko

In a problem involving different coefficients of static and kinetic friction, with static being greater than kinetic, your first objective is to determine whether there is any motion to begin with. For motion to happen, there must be a component of force parallel to the contact surface, whose magnitude is greater than the maximum force of static friction.

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