The pencil has a shadow. is the pencil opaque or transparent?​

Aboy with a mass 25 kg climbs into a small tree. he sits on a branch that is 2.o m above to the ground.what is his gravitational potential energy above the ground?

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.

How to tell if two objects are in thermal equilibrium 1.the objects have the same temperature 2.the objects are the same size 3.the objects are touching each other 4.the objects temperatures are changing