What does it mean when we say that the topological structure of phase space of a two-dimensional simple harmonic oscillator corresponds to a "torus"?

Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called

Matter that emits no light at any wavelength is called

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s