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GATE 2020 ME (ME2) – Question 15

Engineering Mechanics · Free-body diagrams and equilibrium · 1 mark · Multiple choice

A roller of weight W is pulled over a curb by a horizontal force F as shown. Static friction coefficient at the ground and step edge is μ. Select the correct free-body diagram when the roller is just about to climb. Choices A, B appear in the top row; C, D in the bottom row.

Diagram for GATE 2020 ME (ME2) question 15
  1. FBD A
  2. FBD B
  3. FBD C
  4. FBD D

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Show answer and explanation

Correct answer: (B) FBD B

Explanation

At impending climb the ground reaction vanishes. The remaining forces are horizontal pull F, weight W, and the resultant contact reaction at the step corner. These three forces must be concurrent for equilibrium. The resultant at the corner need not pass through the centre because friction contributes. **B** shows the correct three-force FBD.