Correct answer: 5 N
The maximum static friction force is given by \( f_s = \mu_s \cdot m \cdot g \), where \( \mu_s = 0.6 \), \( m = 1 \) kg, and \( g = 9.8 \, \text{m/s}^2 \). This gives \( f_s = 0.6 \cdot 1 \cdot 9.8 = 5.88 \, \text{N} \). However, the required frictional force to prevent slipping is \( f = m \cdot a = 1 \cdot 5 = 5 \, \text{N} \), which is less than the maximum static friction. Thus, the frictional force acting is 5 N.