Posted by Karla on Thursday, August 30, 2012 at 8:03pm.
Assume a block on unknown weight rests on an incline of 25 degrees and is initially not moving. What push (P) is required to start moving the block if the coefficient of static friction is 0.7?

Physics  Elena, Friday, August 31, 2012 at 4:21am
If we want the bloch to move downward along incline:
P=F(fr)m•g•sinα =μ•m•g•cosα  m•g•sinα = m•g(μ •cosα – sinα)
If we want the block to move downward along incline:
P=F(fr)+m•g•sinα =μ•m•g•cosα + m•g•sinα = m•g(μ •cosα +sinα)