Ahand lifts a block vertically upward at constant velocity. the work done by gravity on the block if the system consists of the block only. and why?
a) is zero,
b) is zero/is zero,
c) is negative/is zero,
d) is positive/is negative,
e) is negative/is positive,
f) is positive

(e)

Explanation:

If block is raised vertically upward then work done by force F to height h is given by

Work done by gravity will be equal and opposite to the work done by force F as object is moving with constant velocity i.e. net force on object is zero.

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods