- #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