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ENGR5004 / Week 7
Dynamics L13 Worked example 1TutorialOld spec ENGR2162:212 min

ENGR216 Dynamics L13 worked example 1 (slides 12-13) official answers

A 5 m rod AB has rollers at both ends: A runs down a vertical wall and B runs along the horizontal floor to the right of the wall. At the instant shown A is 4 m above the floor (so B is 3 m from the wall), and A is moving down at vA=6v_A = 6 m/s with a downward acceleration aA=5a_A = 5 m/s2^2.

Find the angular velocity and angular acceleration of the rod and the acceleration of B at this instant.

Rod AB (5 m): roller A on the vertical wall, 4 m above roller B on the floor; A moves down with v_A = 6 m/s and a_A = 5 m/s^2.
Rod AB (5 m): roller A on the vertical wall, 4 m above roller B on the floor; A moves down with v_A = 6 m/s and a_A = 5 m/s^2.
Formulas you may need
  • Instantaneous centre: ω=vA/rA/IC\omega = v_A/r_{A/IC} (learn this)
  • Relative acceleration: aB=aA+α×rB/A−ω2rB/A\mathbf a_B = \mathbf a_A + \boldsymbol\alpha \times \mathbf r_{B/A} - \omega^2\mathbf r_{B/A} (learn this)