Figure shows a heavy block kept on a frictionless surfaces and being mass m. At `t=0`, the

Figure shows a heavy block kept on a frictionless surfaces and being mass m. At `t=0`, the force on the left rop is withdrawn but the force on the right end continues to act. Let `F_(1) and F_(2)` be the magnitudes of the forces acting on the block by the right rope and the left rope on the block respectively, then