Question

a 2000 lb block lies on a smooth plaane at 50 degrees with the horizontal. Find the horizontal force needed to hold the block on the inclined plane.

Answer 1

Let's apply the Newton's Second Law of Motion:

$$F_h-mgsin\theta=0,$$ $$F_h=mgsin\theta,$$ $$F_h=2000\ lb\cdot\dfrac{0.453592\ kg}{1\ lb}\cdot9.8\ \dfrac{m}{s^2}\cdot sin50^{\circ}=6810\ N.$$