PLZ HURRY NEED HELP ASAP Three components in a parallel circuit have individual resistances of r1, r2, and r3. What formula can you use to determine the total resistance of the circuit?

A. R=r1+r2+r3

B. R=1r1+1r2+1r3

C. 1R=r1+r2+r3

D. 1R=1r1+1r2+1r3

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

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.

Amaterial that provides resistance to the flow of electric current is called a(an) (1 points)