A Martian rover found an interesting rock that could contain signs of what Mars was like long ago. It grabbed it with its rover arm and raised it to a height of 0.2 m. Then it dropped it and found that it had a kinetic
energy of 12 J when it struck the ground. Note that Mars has an acceleration due to gravity of 3.77 m/s2.
Complete the following equations to determine the rock's potential energy if it were brought to earth and
dropped from a height of 1 meter. Use what you know about calculating gravitational potential energy to
correctly set up and solve the equation.
PE- m
XH
- PE

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

Does work output exceed work input when a machine is used? a) yes, it does, as machines create energy. b) it depends on the type of machine used. c) no, it doesn’t, as machines are inefficient. d) no, it doesn’t, as machines cannot create energy.

An object's buoyant force and weight mean the same thing.a. trueb. false