The Lewis symbol

would be characteristic of which group?



a.

6A



b.

8A



c.

3A



d.

7A

---

b

Physics & Space Science

Suppose you are observing a distant galaxy whose light has taken 12 billion years to reach us. What is the maximum age that this galaxy could have been when it emitted the light we are observing now? (Assume the age of the universe is about 14 billion years.)

A) about 2 billion years old B) about 10 billion years old C) about 4 billion years old D) about 12 billion years old

Only two forces act on a 3.0-kg mass. One of the forces is 9.0 N east, and the other is 8.0 N in the direction of 62° north of west. What is the magnitude of the acceleration of the mass?

a. 2.0 m/s2 b. 2.4 m/s2 c. 3.3 m/s2 d. 2.9 m/s2 e. 5.7 m/s2

A particle (mass = 5.0 g, charge = 40 mC) moves in a region of space where the electric field is uniform and is given by Ex = 2.5 N/C, Ey = Ez = 0 . If the velocity of the particle at t = 0 is given by vy = 50 m/s, vx = vz = 0, what is the speed of the particle at t = 2.0 s?

a. 81 m/s b. 72 m/s c. 64 m/s d. 89 m/s e. 25 m/s

Two coherent sources emit waves of 2.0-m wavelength in phase. If the path length to an observer differs by ________, then _________ interference occurs.

A. 1.0 m, constructive B. 2.0 m, destructive C. 3.5 m, constructive D. 7.0 m, destructive E. 8.0 m, destructive