What is the best alternative explanation for the dark matter in the milky way based on the observed orbital motions of stars and gas?

Which of the following statements about motion are true? Select all that apply. A. If an object is changing direction, a force must be acting on it. B. If an object is changing speed, a force may or may not be acting on it. C.

4. You have a frustrating day and just feel like screaming; you grab a pillow to scream into it. Which interaction of sound would take place here, (reflection, refraction or absorption), and how did the sound waves move?

Sort the characteristics of solids, liquids, and gases into the correct columns.

The aging process of a star îs referred to as

The system in Fig. 13-29 is in equilibrium, but it begins to slip if any additional mass is added to the 5.0 kg object. What is the coefficient of static friction between the 10 kg block and the plane on which it rests?

Which of the following statements about degeneracy pressure is not true? a) Black holes form when gravity overcomes neutron degeneracy pressure. b) Degeneracy pressure arises from a quantum mechanical effect that we don't notice in our daily lives.

A bar magnet and a second object are hung from metal rods. The diagram below shows what happens when both objects are released.

Which measurement below has three significant figures? A. 12,300 lbs B. 12.02 m C. 0.2004 g D. 0.018 km

When you stand by the side of a pool someone swimming underwater appears to be in a different location than she really is the effect is called what

A 905 kg test car travels around a 3.25 km circular track. If the magnitude of the centripetal force is 2140 N, what is the car's speed?