Two trains are on separate but parallel tracks running east and west. One has a speed of 90 km/h, the other 80 km/h. Initially, the trains are 5 km apart and are approaching each other. How long will it take the two trains to have the same position along the east-west direction?

What are the theoretical properties of a gas at a temperature of 0 kelvin?

An object has a weight of 500 on earth what is the mass of this object

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)