State PCS PYQPrelims 2025

BPSC – Combined Competitive Examination · প্রশ্ন 121

We apply a force of 200 newtons on a wooden box and push it across the floor at constant velocity. The friction force will be:

  1. 100 N
  2. 200 N
  3. 300 N
  4. 400 N
উত্তর দেখান ও ব্যাখ্যা

উত্তর: (B) 200 N

ব্যাখ্যা

By Newton's first law, zero acceleration means the forces balance: friction = 200 N.

  • (A) ভুল

    Wrong: at constant velocity net force is zero, so friction equals 200 N.

  • (B) সঠিক

    Correct: constant velocity means applied force = friction = 200 N.

  • (C) ভুল

    Wrong: friction cannot exceed the applied force if velocity is constant.

  • (D) ভুল

    Wrong: not balanced with 200 N.