Answer:
fr = 514.5 N, Â Â This force has the opposite direction to the applied force.
Explanation:
Let's propose the solution of the problem using Newton's Second Law, we place a reference frame with the horizontal x-axis
Y axis
     N- W = 0
     N = W
X axis
     F -fr = m a
    Â
the friction force has the expression
    fr = μ N
    fr = μ mg
   Â
    fr = 0.35  150  9.8
    fr = 514.5 N
This force has the opposite direction to the applied force.
The student's answer is incorrect because the friction coefficient must be multiplied by the normal