You stand at the top f a tall building with a stopwatch. you drop a rock off the side of the building, and it takes the rock 1.9 seconds to hit the ground (assume no time resistance)

a. how tall is the building?

b. how fast was the rock going when it hit the ground?

c. when you did your calculation for part (b), you assumed there was no air resistance. would your answer be larger, smaller, or the same if there were air resistance? explain.

Ascrew incorporates which other simple machine? lever wheel and axle inclined plane pulley

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 11.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.80 m/s; (b) he is then lifted at the constant speed of 4.80 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 78.0 kg rescue by the force lifting him during each stage

Which statement is true? a. kepler's laws apply only to the motion of earth. b. kepler's laws can be used to predict eclipses. c. kepler's laws are true for a central force that is directly proportional to distance. d. kepler's laws can be deduced from newton's laws of motion and gravity.