In which eon of Earth's history did dinosaurs and mammals first appear?
A) Hadean
B) Archean
C) Phanerozoic
D) Proterozoic
C
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At the Earth’s orbital distance, the intensity of the solar radiation is approximately 1400 
What is the value for the rms Electric field strength in solar radiation?
A. 726 V/m B. 363 kV/m C. 527 kV/m D. 513 kV/m
Rotational Kinetic Energy: A string is wrapped tightly around a fixed frictionless pulley that has a moment of inertia of 0.0352 kg ? m2 and a radius of 12.5 cm. The string is pulled away from the pulley with a constant force of 5.00 N, causing the pulley to rotate. What is the speed of the string after it has unwound 1.25 m if the string does not slip on the pulley?
A. 2.09 m/s B. 2.36 m/s C. 1.18 m/s D. 3.18 m/s E. 4.95 m/s
A boy on a bicycle approaches a brick wall as he sounds his horn at a frequency 400 Hz. The sound he hears reflected back from the wall is at a frequency 408 Hz
At what is the speed is the boy riding his bicycle toward the wall? Assume the speed of sound in air is 340 m/s. A) 3.68 m/s B) 333 m/s C) 6.67 m/s D) 6.80 m/s E) 3.37 m/s
When starting from rest at the bottom of a straight road with constant upward slope, Joan bicycles to the top 50.0 s ahead of Sally, whose travel time is 5.00 minutes. What is the ratio of Joan's acceleration to Sally's acceleration?
a. 0.694 b. 0.833 c. 1.20 d. 1.44 e. 6.00