- #1
DigitalSpark
- 19
- 0
Homework Statement
Okay here's the first question which I done:
"Question 5: A body of mass 2kg is held in limiting equilibrium on a rough plane inclined at 20 degrees to the horizontal by a horizontal force X. The coefficient of friction between the body and the plane is 0.2. Modelling the body as a particle find X when the body is on the point of slipping:
a) up the plane.
b) down the plane."
It's the next question (which builds up on 5) which I'm having difficulty with.
"Question 6: The force X in Question 5 is replaced by a force Y at an angle of 45 degrees to the horizontal. Find Y when the body is on the point of slipping down the plane."
Homework Equations
The Attempt at a Solution
Okay the answer in the book says 3.67N when I get 5N. I think I'm right but I can't be sure.
Heres my method:
Rn=mgcos20 + Ysin65 ---- Equation 1
Ff+Ycos65=mgsin20 ---- Equation 2
[tex]\mu[/tex]mgcos20+[tex]\mu[/tex]Ysin65+Ycos65=mgsin20
Y([tex]\mu[/tex]sin65+cos65)=mgsin20-[tex]\mu[/tex]mgcos20
Y=[tex]\frac{mgsin20-\mu mgcos20}{\mu sin65+cos65}[/tex] [tex]\approx[/tex]5N