Author Question: A mass vibrates back and forth from the free end of an ideal spring (k = 20. N/m) with an amplitude ... (Read 74 times)

theo · **on:** Jul 27, 2018

A mass vibrates back and forth from the free end of an ideal spring (k = 20. N/m) with an amplitude of 0.30 m. What is the kinetic energy of this vibrating mass when it is 0.30 m from its equilibrium position?

A) 1.4 J
B) 0.90 J
C) zero
D) 0.45 J
E) It is impossible to give an answer without knowing the object's mass.

Question 2

A brass rod, 4.0 m long and with a cross sectional area of 9.2 10-6 m2 is subjected to a tension of 6.0 103 N/m2. The Young's modulus for brass is 9.0 1010 N/m2, and the Poisson ratio is 0.48. By how much does the volume of the rod change?

A) 6.3 10-7 m3
B) 0.029 m3
C) 2.7 10-7 m3
D) 4.0 10-7 m3
E) 5.2 10-7 m3