The 1kg cart starts rolling without friction from rest at position and subsequently strikes the 3kg block as shown in Figure. Block B is connected to point O with a light rigid rod, which can rotate around O. The coefficient of restitution for the collision is e = 0.7, determine approximately the speed of block (in m/s) when it is at a height of 1.1 m above the ground. Neglect friction.

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⇒ u = 12 m/s

1 × 12 + 3 × 0 = 1 × v1 + 3 × v2
12 = 4v2 8.4 ⇒ v2 = 5.10 m/s