Question

A rubber ball filled with air has a diameter of 25.1 cm and a mass of 0.618 kg. What force is required to hold the ball in equilibrium immediately below the surface of water in a swimming pool?


I tried using the equation
B = density(fluid)volume(object)g
B = 1.0E3(4/3(pi)(.1255^3))(9.8)

and I got 81.14 and it says that I am off by 10% so I know I am close...but I can't get it to accept my answer.

Answer 1

You have to subract the weight of the ball from that. It is 5.87 N. That reduces the force you need to submerge ball.

You are actually about 8% off.

Answer 2

thanks again