A ball is shot up from the ground with an initial vertical velocity of 30 m/s. What is the final velocity of the ball right
before it returns to the ground?

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

Is a volume of space that is empty of matter.

Estimate the kinetic energy of mars with respect to the sun as the sum of two terms, that due to its daily rotation about its axis, and that due to its yearly revolution about the sun. (assume mars is a uniform sphere with mass = 6.4×10 to the power of 23 kg, radius = 3.4×10 to the power of 6 m, rotation period = 24.7 hours, orbital period = 686 days and is 2.3×10 to the power of 8 km from the sun.)