A mass–spring–damper is described by y″ + 9.6y′ + 64y = 0. Compare it with y″ + 2ζωny′ + ωn²y = 0 and find the damping ratio ζ.
Differential equations worksheet with answers
1.Easy
y″ + 9.6y′ + 64y = 0
ζ =
2.Easy
For the equation y″ + 3y′ + 2y = 0, find the root r of the characteristic equation that is closest to zero. It sets how slowly the solution dies out.
y″ + 3y′ + 2y = 0
r =
3.Medium
Solve y″ + 8y′ + 16y = 0 with y(0) = 1 and y′(0) = 1. Find y(1.5).
y″ + 8y′ + 16y = 0y(0) = 1y′(0) = 1
y(1.5) =
4.Medium
Solve y″ + 6y′ + 8y = 0 with y(0) = 2 and y′(0) = 4. Find y(0.5).
y″ + 6y′ + 8y = 0y(0) = 2y′(0) = 4
y(0.5) =
5.Hard
A system obeys y″ + 4y′ + 20y = 100 for t ≥ 0, starting from rest: y(0) = 0, y′(0) = 0. Find y(1); angles in radians.
y″ + 4y′ + 20y = 100y(0) = 0y′(0) = 0
y(1) =
6.Hard
Solve y″ + 4y′ + 8y = 0 with y(0) = 3 and y′(0) = 0 (released from rest). Find y(1.5); angles in radians.
y″ + 4y′ + 8y = 0y(0) = 3y′(0) = 0
y(1.5) =
Answer key
- 1. ζ = 0.6
- 2. r = −1
- 3. y(1.5) = 0.02107
- 4. y(0.5) = 1.666
- 5. y(1) = 5.698
- 6. y(1.5) = −0.1268
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