Three balls with the same radius 21 cm are in water. Ball 1 floats, with

half of it exposed above the water level. Ball 2, with a density 893

kg/m3 is held below the surface by a cord anchored to the bottom of the

container, so that it is fully submerged. Ball 3, of density 1320 kg/m3, is

suspended from a rope so that it is fully submerged. Assume the

density of water is 1000 kg/m3 in this problem.

A. Which is true for Ball 1?

B. What is the tension on the rope holding the second ball, in newtons?

C. What is the tension on the rope holding the third ball in N?

Question

Physics

Ryan Sparks

16 August, 08:24

Three balls with the same radius 21 cm are in water. Ball 1 floats, with

half of it exposed above the water level. Ball 2, with a density 893

kg/m3 is held below the surface by a cord anchored to the bottom of the

container, so that it is fully submerged. Ball 3, of density 1320 kg/m3, is

suspended from a rope so that it is fully submerged. Assume the

density of water is 1000 kg/m3 in this problem.

A. Which is true for Ball 1?

B. What is the tension on the rope holding the second ball, in newtons?

C. What is the tension on the rope holding the third ball in N?

+5

Answers (1)

Know the Answer?

Clayton Huffman · Answer 1

A)

The ball floats with half of it exposed above the water level. So it must have density half that of water. In other words its density must have been 500 kg / m³

B)

Tension in the ball will be equal to net force acting on the ball

Net force on the ball = buoyant force - weight.

4/3 x π x. 21³ x 10⁻⁶ x 9.8 (1000 - 893)

= 40.65 x 10⁻⁶ N.

C) Tension in the 3 rd ball will be equal to net force acting on the ball

Net force on the ball = weight - buoyant force

= 4/3 x π x. 21³ x 10⁻⁶ x 9.8 (1320 - 1000)

= 121.6 x 10⁻⁶ N.