Answer:
[tex]R-mg cos \theta = 0[/tex], R = 46.0 N
Explanation:
For an object on a ramp, there are two forces acting along the direction perpendicular to the ramp:
- The normal reaction of the surface, N, out of the ramp
- The component of the weight perpendicular to the ramp, in the opposite direction, of magnitude
[tex]mg cos \theta[/tex]
where
m is the mass of the block
[tex]g=9.8 m/s^2[/tex] is the acceleration of gravity
[tex]\theta[/tex] is the angle of the ramp
The box is in equilibrium along this direction, so the equation of the forces in this direction is
[tex]R-mg cos \theta = 0[/tex]
In this problem,
m = 5 kg
[tex]\theta=20^{\circ}[/tex]
So we can find the normal reaction:
[tex]N=mg cos \theta = (5)(9.8)(cos 20)=46.0 N[/tex]