Explanation:
We anticipate him to figure out that a pendulum clock in a weightless world (like orbiting the Earth) does not work at all.
Where the weight is W= m(g-a) in which the mass is m, the momentum is g and the acceleration is.
Weightless' indicates g= a. It doesn't mean g= 0, When g was zero you'd stop spinning and go off running in a straight line.