MCAT Question A Day - 1/3/14 - Answer!
What is the speed of a longitudinal sound wave in a steel rod if Young’s modulus for steel is 20 x 1010 N/m2, and the density of steel is 8 x 103 kg/m3?
A. 4.0 x 1028 m/s
B. 5.0 x 103 m/s
C. 25 x 106 m/s
D. 2.5 x 109m/s
Want more questions? - Click here to check out our MCAT Question A Day archive
The correct answer is (B). The relationship between speed and Young’s modulus is:
v = (Y / rho)1/2
= [ (20 x 1010 kg m/s2) / (8 x 103 kg/m3) ]1/2
= (25 x 106 m2/s2)1/2
= 5 x 103 m/sWant more questions? - Click here to check out our MCAT Question A Day archive
