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ENGR5004 / Week 7
Dynamics L14 Worked example 1TutorialOld spec ENGR2162:210 min

ENGR216 Dynamics L14 worked example 1 (slides 13-14) official answers

A uniform 50 kg crate, 1 m wide and 1 m high, rests on a horizontal surface with kinetic friction coefficient μk=0.2\mu_k = 0.2. A horizontal force P=600P = 600 N is applied to its left face at a height of 0.8 m above the floor. Take g=9.81g = 9.81 m/s2^2.

Find the acceleration of the crate, and show whether it slides or tips.

1 m by 1 m crate on a rough floor; horizontal force P = 600 N applied to the left face 0.8 m above the floor.
1 m by 1 m crate on a rough floor; horizontal force P = 600 N applied to the left face 0.8 m above the floor.
Formulas you may need
  • Rigid-body translation: ∑Fx=m(aG)x\sum F_x = m(a_G)_x, ∑Fy=m(aG)y\sum F_y = m(a_G)_y, ∑MG=0\sum M_G = 0 (learn this)
  • Kinetic friction F=μkNF = \mu_k N; tipping when the resultant normal force reaches the edge of the base (learn this)