Pattern of stars within a constellation, or composed of a number of constellations

The big bang is thought to have occurred about

A) 14 trillion years ago. B) 14 million years ago. C) 5000 years ago. D) a million years ago. E) 14 billion years ago.

Two bodies with masses m1 and m2 are both moving east with velocities of magnitudes v1 and v2, where v1 is less than v2 . The magnitude of the velocity of the center of mass of this system of two bodies is

a. less than v1. b. equal to v1. c. equal to the average of v1 and v2. d. greater than v1 and less than v2. e. greater than v2.

A 12,000-N car is raised using a hydraulic lift, which consists of a U-tube with arms of unequal areas, filled with incompressible oil with a density of 800 kg/m3 and capped at both ends with tight-fitting pistons

The wider arm of the U-tube has a radius of 18.0 cm and the narrower arm has a radius of 5.00 cm. The car rests on the piston on the wider arm of the U-tube. The pistons are initially at the same level. What is the force that must be applied to the smaller piston in order to lift the car after it has been raised 1.20 m? (For purposes of this problem, you can neglect the weight of the pistons.) A) 0.954 kN B) 1.88 kN C) 1.96 kN D) 3.67 kN E) 1.20 kN

What happens to a star's core as the hydrogen there is used up?

A. Nothing. It just turns to helium. B. It contracts and cools. C. It contracts and heats. D. It expands and cools. E. As the helium accumulates, the core rises to the surface of the star and escapes into space.