A 200kg block is going down a frictionless surface on a 20 degree ramp (down the ramp is positive and up the ramp is negative). The horizontal is under a restraining force of 678N acting parallel to the incline. What is the magnitude of acceleration?

Respuesta :

Magnitude of acceleration is 3.35 m/[tex]s^{2}[/tex]

Explanation:

  • Here, the box is sliding down in a frictional force. When we draw the free body diagram, the forces acting on it are normal force and gravitational force.
  • We know that normal force would act in a perpendicular direction.
  • The gravitational force has x and y components since it is sliding down. These two components are mg cosθ and mg sinθ, where θ is the angle of the ramp. Since the motion is along the x-direction, the force act on it is mg sinθ.
  • According to Newton's second law, F = ma, to find acceleration a = [tex]\frac{F}{m}[/tex]  
  • When you substitute the x-axis force, the equation will simplify into

a = g sinθ, so the answer is 3.35 m/[tex]s^{2}[/tex]