Physics
posted by Karla on .
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?

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)