I have this question: If the diesel engine coasts at 4.8 km/h into a freight car that is initially at rest, find the speed of the coupled cars. Now I'm looking at the work done, on the answers given but I'm not understanding where the 5.8 coming in to play?

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?