Of one of the planets becomes a black hole , what would the escape speed be?

Ahorizontal wire is tied to supports at each end and vibrates in its second-overtone standing wave. the tension in the wire is 5.00 n, and the node-to-node distance in the standing wave is 6.28 cm. (a) what is the length of the wire? (b) a point at an anti- node of the standing wave on the wire travels from its maximum upward displacement to its maximum downward displacement in 8.40 ms. what is the wire's mass?

The consumption of fossil fuels could be

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?