physics help please...
posted by julie on .
A light spring of constant k = 170 N/m rests vertically on the bottom of a large beaker of water. A 5.70 kg block of wood (density = 650 kg/m3) is connected to the spring and the mass-spring system is allowed to come to static equilibrium. What is the elongation, ÄL, of the spring?
im using the equation of the spring constant... F=kx F being B-weight. and i keep coming up with the wrong answer. please help me!!!
volume of wood = (5.7/650) m^3
difference in density = 1000-650 = 350 kg/m^3
net force up = 350 (5.7/650)(9.81) = 30.1 N
F = k x
30.1 = 170 x
x = 30.1/170 = .177 meter
why is the difference in density 350? where does the 1000 come from?
water density = 1,000 kg/m^3
close enough :)
the 1000 kg/m^3 is the density of water.
I used the difference in wood and water density to get the net buoyancy.