A small metal sphere weighs 0.26 N in air and
has a volume of 15.7 cm^3
What is the acceleration of the sphere as
it falls through water? The acceleration of
gravity is 9.8 m/s2 .
Answer in units of m/s2

Question

A small metal sphere weighs 0.26 N in air and
has a volume of 15.7 cm^3 
What is the acceleration of the sphere as
it falls through water? The acceleration of
gravity is 9.8 m/s2 .
Answer in units of m/s2

anonymous · Answer

The 0.26 N force of gravity will be offset by the buoyancy, (15.7 gm water) g
which is (0.0157 kg)(9.8N/kg) = 0.147 N. That net force, 0.26N - 0.15N=0.11N
will act on the mass, but so will resistance due to the water, not considered here. 
The answer sought may be (0.11/0.26) g, but this is a poor question.