Arock is thrown straight up into the air. at the
highest point of the rock’s path, the magnitude of
the net force acting on the rock is
(1) less than the magnitude of the rock’s weight,
but greater than zero
(2) greater than the magnitude of the rock’s
weight
(3) the same as the magnitude of the rock’s
weight
(4) zero

If gases like carbon dioxide and methane make up less than 1% of the total atmosphere, why is it important for scientists to monitor changes in percentages of these gases?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

What is the single most important equation in all of physics?