I WILL JUST GIVE U A BRIEF

OUTLINE IF U CANT SOLVE THEN NUDGE ME

SEE FIRSTT FIND OUT THE MIMENTUM OF THE SYSTEM AT THE END OF 5S, THIS WILL BE IN THE UWARD DIRECTION

THIS WILL BE CONSERVED

AFTER THAT THE MOMENTUM OF THE FALLING PARTICLE WILL BE NEGATIVE

WE HV TO FIND THE INITAL VELOCITY SINCE

25 IS THE FINAL VELOCITY NOT THE INTIAL

SO V^2=U^2+2AS

OR U CAN FIND IT OUT BY ANY OTHER METHI

SO CONSERVE THE MOMENTUM AND GET THE ANSWER

PLZ RATE ME IF U FIND ME USEFUL

!!!!CHEERS!!!!!!