PLEASE HELP You drop a large rock from a 19 story building. It is 78 meters high. The wind is blowing from the southwest at 3.5 m/s.

What is the initial velocity of the rock?
How long will it take to hit the pile of leaves that are sitting below?

For a particular reaction, ? h = -144.6 kj and ? s = -301.2 j/k. calculate ? g for this reaction at 298 k.

What is relative velocity? in which condition is relative velocity known by adding the velocity of the first body and that of the second body

Three different objects, all with different masses, are initially at rest at the bottom of a set of steps. each step is of uniform height . the mass of each object is a multiple of the base mass : object 1 has mass 4..00m , object 2 has mass 1..96m , and object 3 has mass . when the objects are at the bottom of the steps, define the total gravitational potential energy of the three-object system to be zero. if the objects are then relocated as shown, what is the new total potential energy of the system? each answer requires the numerical coefficient to an algebraic expression. each algebraic expression is given using some combination of the variables , , and , where is the acceleration due to gravity. enter only the numerical coefficient. (example: if the answer is 1..23mgd , just enter 1.23)