Mechanical vibrations worksheet with answers

Free printable Mechanical vibrations worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
k = 10 kN/mm = 5 kgx

A 5 kg mass hangs from a spring with a stiffness of 10 kN/m. Ignore damping. Find the natural circular frequency ωn in rad/s.

m = 5 kgk = 10 kN/m
ωn = rad/s
2.Easy
k = 50 kN/mm = 500 kgx

A 500 kg mass hangs from a spring with a stiffness of 50 kN/m. Ignore damping. Find the natural frequency fn in Hz.

m = 500 kgk = 50 kN/m
fn = Hz
3.Medium
k = 40 kN/mc = 130 N·s/mm = 40 kg

A 40 kg mass is supported by a spring with a stiffness of 40 kN/m and a viscous damper with a damping coefficient of 130 N·s/m. Find the damping ratio ζ.

m = 40 kgk = 40 kN/mc = 130 N·s/m
ζ =
4.Medium
k = 15 kN/mc = 930 N·s/mm = 40 kg

A 40 kg mass is supported by a spring with a stiffness of 15 kN/m and a viscous damper with a damping coefficient of 930 N·s/m. Find the damping ratio ζ.

m = 40 kgk = 15 kN/mc = 930 N·s/m
ζ =
5.Hard
k1​ = 25k2​ = 30m = 25 kg

A 25 kg mass hangs from two springs side by side (in parallel), with stiffnesses k₁ = 25 kN/m and k₂ = 30 kN/m. The mass stays level. Ignore damping and the masses of the springs. Find the natural frequency fn of vertical vibration in Hz.

m = 25 kgk1 = 25 kN/mk2 = 30 kN/m
fn = Hz
6.Hard
k1​ = 10k2​ = 50m = 5 kg

A 5 kg mass hangs from two springs side by side (in parallel), with stiffnesses k₁ = 10 kN/m and k₂ = 50 kN/m. The mass stays level. Ignore damping and the masses of the springs. Find the natural frequency fn of vertical vibration in Hz.

m = 5 kgk1 = 10 kN/mk2 = 50 kN/m
fn = Hz

Answer key

  1. 1. ωn = 44.72 rad/s
  2. 2. fn = 1.592 Hz
  3. 3. ζ = 0.05139
  4. 4. ζ = 0.6003
  5. 5. fn = 7.465 Hz
  6. 6. fn = 17.43 Hz

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