Question

A youngster is holding a ball with a diameter of 4.00 cm and average density of 0.0845 g/cm^3 under water. Determine the force (in N) needed to hold it completely submerged.

Answer 1

Answer:

Explanation:

diameter = 4 cm

radius, r = diameter/ 2  = 2 cm

density, d = 0.0845 g/cm³

True weight, W = mg = volume x density x g

$W= \frac{4}{3}\times 3.14\times 2\times 2\times 2\times 0.0845\times 980$

W = 2773.6 N

Buoyant force acting on the sphere

B = Volume of sphere immersed x density of water x gravity

$B= \frac{4}{3}\times 3.14\times 2\times 2\times 2\times 1\times 980$

B = 32823.5 N

The amount of force to hold the sphere is

F = Buoyant force - Weight

F = 32823.5 - 2773.6 = 30049.9

F = 30050 N