In the arrangement shown in the figure, masses 6 kg and 2 kg are connected by a light inextensible string passing over a massless pulley. The 6 kg mass is released from rest when it is 6 m above the ground. Taking g = 10 m·s⁻², what is its speed just before it strikes the ground?

Question

G1 Physics · Accepted Answer

As the 6 kg mass descends by 6 m, the 2 kg mass rises by 6 m. Net decrease in gravitational potential energy is ΔU = (6-2)gh. This becomes the total kinetic energy of the two masses: (6-2)(10)(6) = (1 ÷ 2)(6+2)v². Thus, 240 = 4v², v² = 60. Therefore, v = √60 ≈ 7.746 m·s⁻¹. Hence the closest option is 7.74 m·s⁻¹. Correct option: A.