Which of the following is a safe assumption about all the stars in a star cluster?
A) They all have approximately the same surface temperature.
B) They are all approximately the same distance away from us.
C) They all have approximately the same mass.
D) They will all have approximately the same lifetimes.
E) They all have approximately the same apparent brightness in our sky.
B) They are all approximately the same distance away from us.
You might also like to view...
A 1.5m long dowel (a cylindrical rod) is pivoted about the end so that it is a pendulum of sorts - it can freely swing in a vertical plane. The dowel has a diameter of 2.0cm, and its density is 3.2 
When it is positioned in its swing such that its angle with the vertical is 22.5 degrees, what is the torque on the rod about the pivot due to its weight?
A. 17Nm B. 42Nm C. 11Nm D. 10Nm E. 44Nm F. 41 Nm
As an object of mass 60 kg approaches the bottom of a ramp, point A, its speed is 20 m/s. It goes up the frictionless plane and turns around at point B. What is the potential energy of this object at point B? Use g = 10 m/s2
A) 0 J B) 6.0 × 103 J C) 9 × 103 J D) 12 × 103 J E) 18 × 103 J
Of all the planets, the axial tilt and rotation period of ________ is most like our own
A) Earth B) our Moon C) Venus D) Mars E) Mercury
A light ray strikes the surface of sapphire (n = 1.77) at an angle of incidence of 
What angle of refraction results?
A. 
B. 
C. 
D. 
E. 