You stand at the top of a tall building with a stopwatch. You drop a rock off the side of the building, and it takes the rock 3.2 seconds to hit the ground. (Assume no air resistance.) Solved for : The building is 50.176 meters tall. The impact speed is 31.36 m/s Question: . If you were standing at the bottom of this building, at what speed would you have to throw the rock for it to reach the top of the building?

A23 kg log of wood begins from rest, 300 m up a sluice (a water track used to transport logs, think of it as an inclined plane with negligible friction) inclined at 20° to the horizontal. after it reaches the flat waterway at the bottom it collides elastically with a 100 kg block of wood initially at rest near the base of the incline. (a) how long does it take the 23 kg log to travel down the incline? (b) what is the speed of the 23 kg log at the bottom of the incline? (c) what are the velocities of both blocks of wood after the collision? (d) what is the total kinetic energy before the collision? (e) what is the kinetic energy of the 23 kg log after the collision? (f) what is the kinetic energy of the 100 kg block of wood after the collision? (g) what is the total kinetic energy after the collision? (h) compare the total initial and total final kinetic energies. is this consistent with what you would expect for elastic collisions? explain!

In automobile steering wheel is shown what is the ideal mechanical advantage blank? if the ama is eight what is the efficiency of the steering wheel?

Aspectroscope breaks light up into its colors, allowing scientists to analyze light from the solar system and universe. by studying the spectral line patterns, widths, strengths and positions, scientists can determine the speed, position, and of celestial bodies. a) age b) origin c) rotation d) temperature