A cube with sides of length 2a and mass M is moving with an initial speed v₀ along a frictionless table. When the cube reaches the end of the table it is caught abruptly by a short lip and begins to rotate. The minimum speed v₀ such that the cube falls off the table is:-

Question

G1 Physics · Accepted Answer

During the impulsive catch at the lip, angular momentum about the lip is conserved. Just after impact, equate the post-impact rotational kinetic energy to the increase in gravitational potential energy needed for the centre of mass to pass over the lip. This gives v₀ = √[16ag(√2-1)/3]. Hence A.