1. The problem statement, all variables and given/known data A pendulum clock in the centre of a large room is observed to keep correct time. How many seconds per year will the clock gain if the floor is covered by a 1m thick layer of lead of density 11350kgm^-3 ? Newtons gravitational constant is G = 6.67 x10^-11 Nm^2 kg^-2 2. Relevant equations 3. The attempt at a solution Im not sure if its relevant to use but i thought i could use the equation for a pendulum T = pi(l/g)^1/2 Any ideas?