Alex has to pick up a 20 N stack of documents and raise them 5 meters from the floor.

A. How much work does Alex do on the stack of documents as he lifts it?

B. While Alex is holding the documents, what type of energy do they have relative to the floor?

C. Alex gets tired and drops the documents to the floor. As the stack falls, what type of energy does it possess?

Arod of some material 0.20 m long elongates 0.20 mm on heating from 21 to 120°c. determine the value of the linear coefficient of thermal expansion [in (degrees c)^-1] for this material.

What is the angular momentum of the bar about the axle?

Aboat radioed a distress call to a coast guard station. at the time of the call, a vector a from the station to the boat had a magnitude of 45.0 km and was directed 15.0° east of north. a vector from the station to the point where the boat was later found is = 30.0 km, 15.0° north of east. what are the components of the vector from the point where the distress call was made to point where the boat was found? in other words, what are the components of vector c = b - a?