In fig. la and fig.1 b above, Ida and Wb represent the respective loads on a spring placedtiear a 30 cm rule, when in air and when in water:
(a) Identify the force causing a shrink in the spring in fig.(b).
(b) Given that the force constant of the spring is 2.0 x 10\(^{11}\) Nm\(^{-1}\), calculate the work done by the force in causing the shrink.
Explanation
(a) The force causing a shrink is the upthrust of the water.
(b) Work done = \(\frac{1}{2}ke^2\)
= \(\frac{1}{2}(2 \times 10^{11}) \times (2 \times 10^{-2})^2\) = 4.0 x 10\(^7\)