force analysis

Question

A block of mass 3 kg is pushed against a vertical wall by a horizontal force of 50 N. If the coefficient of static friction is 0.6, what is the static friction force acting on the block? (Use g = 10 m/s²)

RankGuru · Accepted Answer

1. **Normal Force**: The wall pushes back horizontally with $N = 50$ N.
2. **Downward Force**: Object's weight $W = mg = 3 	imes 10 = 30$ N.
3. **Available Friction**: $f_{max} = \mu_s N = 0.6 	imes 50 = 30$ N.
4. **Comparison**: The downward active force ($30$ N) is equal to or less than the maximum possible friction ($30$ N).
5. **Result**: Since it is the static case, friction **matches** the weight to maintain equilibrium. Force acting is **30 N**.

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force analysis

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