# Working out tension of string holding a ball underwater

I have a physics homework question that i need help with;
A submerged ball of negligible mass is attached to the bottom of a swimming pool by two strings as shown. The volume of the ball is 5000cm^3. Calculate the tension in each string. (hint you need to look up the density of water)

How do i do this? Do i use the buoyancy of the ball or the tension formula?

The
triangle with the base being the bottom of the pool and the ball being attached to the top vertex with a 60 degree angle

## Answers and Replies

What you need to do is a force balance on the ball.

So there is a gravitational force, a buoyancy force and tension forces all acting on the ball, which is not moving. What does that tell you?

Alice Martin
What you need to do is a force balance on the ball.

So there is a gravitational force, a buoyancy force and tension forces all acting on the ball, which is not moving. What does that tell you?
Thank you!! That is a really simple way of putting it. I did not even think about the fact that the forces must be equal!!!

Drakkith
Staff Emeritus