A mass m is placed on a very smooth wedge resting on a rough surface with friction coefficient μ. Once the mass is released, the acceleration to be given to the wedge so that m remains at rest is a, where
1
a = g sin θ + μg cos θ
2
a = g tan θ - μg
3
a = g sin θ - μg
4
a = g tan θ + μg