An astronomical unit (au) is equal to the average distance from earth to the sun, about 92. 9 × 10^6 mi. A parsec (pc) is the distance at which a length of 1 au would subtend an angle of exactly 1 second of arc (the figure). A light-year (ly) is the distance that light, traveling through a vacuum with a speed of 186000 mi/s, would cover in 1. 0 year. Express the earth–sun distance in (a) parsecs and (b) light-years.

What is the rate of change in a objects position?

Astone weighing 1.5 kilograms is resting on a rock at a height of 20 meters above the ground. the stone rolls down 10 meters and comes to rest on a patch of moss. the gravitational potential energy of the stone on the moss is joules.

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.