A mass of 10 gm moving with a velocity of 100 cm/s strikes a pendulum bob of mass 10 gm. The two masses stick together. The maximum height (in cm) reached by the system now is (g=10 m/s2)

Initially mass 10 gm  moves with velocity 100 cm/s∴ Initial momentum = 10 × 100 = 1000gm×msecAfter collision system moves with velocity vsys.  then Final momentum =  (10+10)×vsys.By applying the conservation of momentum 10000=20×vsys.⇒vsys.=50 cm​/​sIf system rises upto height h then h=vsys.22g=50×502×1000=2.52=1.25 cm