You push a box of mass 24.9 kg with your car up to an icy hill slope of irregular shape to a height 4.4 m. the box has a speed 14 m/s when it starts up the hill, the same time that you brake. it then rises up to the top (with no friction) before immediately falling off a sheer cliff to the ground (with no drag).
(a) what is the speed of the box at the top of the hill?
(b) what is the direction (unit vector) of the box's velocity just before hitting the ground?

You throw a baseball directly upward at time t = 0 at an initial speed of 12.3 m/s. what is the maximum height the ball reaches above where it leaves your hand? at what times does the ball pass through half the maximum height? ignore air resistance and take g = 9.80 m/s2.

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

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.