A solid aluminum ingot weighs 89 N in air. What is its volume? The ingot is suspended from a rope and totally immersed in water. What is the tension in the rope?

Answer 1

Weight = 89 N
mass, m = 89 N / g
= 9.08 kg
where g=9.8 m/sec²=acc.due to gravity
Density of aluminium, ρ
= 2700 kg/m³
Volume, V= m / ρ m³

When immersed in water, by the principle of floation, its weight is reduced by the weight of liquid it displaced, namely ρVg.
Thus, the tension in the rope, T is given by:
T = 89 N - 1000 (kg/m³) * V (m³) * g