A mass–spring–damper is described by y″ + 12y′ + 100y = 0. Compare it with y″ + 2ζωny′ + ωn²y = 0 and find the damping ratio ζ.
Differential equations worksheet with answers
A mass–spring–damper is described by y″ + 14y′ + 100y = 0. Compare it with y″ + 2ζωny′ + ωn²y = 0 and find the damping ratio ζ.
A forged steel part at 380 °C is left to cool in a workshop at 26 °C. It follows Newton's law of cooling, dT/dt = −k·(T − Tₐ). With k = 0.01 min⁻¹, find its temperature T after 58 min.
A can of soda at 3 °C is taken out of the fridge into a room at 27 °C. After 7 min its temperature is 13 °C. It follows Newton's law of cooling, dT/dt = −k·(T − Tₐ). How long after the start, t, does it take to reach 23 °C?
Solve the initial value problem y′ + 3y/x = 6 for x > 0, with y(1) = 0. Find y(3).
Solve y″ + 2y′ + 26y = 0 with y(0) = 10 and y′(0) = 0 (released from rest). Find y(0.75); angles in radians.
Answer key
- 1. ζ = 0.6
- 2. ζ = 0.7
- 3. T = 224.2 °C
- 4. t = 23.27 min
- 5. y(3) = 4.444
- 6. y(0.75) = −4.416
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