Question 1 A STUDENT TIES A STRING AROUND A WEIGHT AND SWINGS THE WEIGHT IN A CIRCLE AROUND HER BODY. IF
THE STUDENT REPRESENTS THE SUN AND THE WEIGHT REPRESENTS EARTH, WHAT DOES THE STRING
REPRESENT?
A. GRAVITY
B. RADIATION
C. ELECTRICITY
D. MAGNETISM

Which term best describes the phrase “something that happens”?

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

In a game of pool, ball a is moving with a velocity v0 of magnitude v0 = 15 ft/s when it strikes balls b and c, which are at rest and aligned as shown. knowing that after the collision the three balls move in the directions indicated and assuming frictionless surfaces and perfectly elastic impact (that is, conservation of energy), determine the magnitudes of the velocities va, vb, and vc.