Applications to Astronomy: It can be shown that the approximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 
, estimate the age of the universe, in years. (1 ly = 9.46 × 1015 m)
A. 15 thousand years
B. 15 million years
C. 15 billion years
D. 50 billion years
Answer: C
You might also like to view...
In addition to Mars, which jovian moon shows some promise of life, with a surface not that different from the Arctic Ocean?
A) Titan B) Miranda C) Europa D) Io E) Triton
The lift experienced by Maglev trains is due to magnetic
A) attraction. B) repulsion. C) dipoles.
A substance has a melting point of 20°C and a heat of fusion of 3.9 x 104 J/kg. The boiling point is 150°C and the heat of vaporization is 7.8 x 104 J/kg at a pressure of 1.0 atm
The specific heats for the solid, liquid, and gaseous phases are 600 J/(kg?K), 1000 J/(kg?K), and 400 J/(kg?K), respectively. The quantity of heat required to raise the temperature of 3.80 kg of the substance from -61°C to 128°C, at a pressure of 1.0 atm, is closest to A) 620 kJ. B) 470 kJ. C) 560 kJ. D) 210 kJ. E) 770 kJ.
A spring (k = 600 N/m) is at the bottom of a frictionless plane that makes an angle of 30° with the horizontal. The upper end of the spring is depressed 0.10 m, and a 2.0-kg block is placed against the depressed spring. The system is then released from rest. What is the kinetic energy of the block at the instant it has traveled 0.10 m and the spring has returned to its uncompressed length?
a. 2.0 J b. 1.8 J c. 2.2 J d. 1.6 J e. 1.0 J