How Much Force Does Water Exert on a Sandbag Dropped from 315m?

[Brittykitty]

At an altitude of 315 m above a lake, a hot-air balloon pilot drops a 2.50 kg sandbag. If the bag comes to a stop 4.50 m below the surface of the lake, what force was applied by the water on it?

I was thinking v= 2.50kg x 9.81km/h= 24.525m/s
i can't remember how to get the force

 

[rock.freak667]

Like I replied in your other thread with the same problem, use the law of conservation of energy.

Work=force*distance.