Question

A spiral spring loaded with a piece of metal extends by 10.5cm in air. When the mental is fully submerged in water, the spring extends by 6.8cm. Calculate the relative density of the metal assumming hookes is obeyed.

Answer 1

water density = 1000 kg/m^3
F = k x
m g = k (0.105)
k = m g /0.105
now in water , volume = v
F = k (0.068) = m g - 1000 g v
(m g/0.105)0.068 = m g - 1000 g v
m (.648) = m - 1000 v
-.352 m = -1000 v
m/v = 2840 kg/m^3
relative to water = 2.84
check my arithmetic carefully !

Answer 2

Easy to understand

Answer 3

10.5/10.5 -6.8
=10.5/3.7
=2.84

Answer 4

This calculates the relative density of the metal as 2.84 assuming Hooke's Law is obeyed.