This book describes the main methods used to analytically solve first order ordinary differential equations (ODE). First order ODE equations are introduced including details of their classification by order and degree. The main analytical, techniques are then presented with a number of worked exampl READ MORE »
- Responses: 198
- eBooks: 1
- M.Sc, University of Surrey, UK, 2008
- M.Eng, Open University in the UK, 2004
- B.Sc (hons) 2(2), Leicester University in the UK, 1985
1. For the circuit given in FIGURE 1 the power factor is 0.72 lagging and the power dissipated is 375 W.
FIG. 1 (see attachment)
(i) apparent power
(ii) reactive power
(iii) the magnitude of the current flowing in the circuit
(iv) the value of the impedance Z and state whether READ MORE »
Write down an expression for the voltage waveform, and sketch the waveforms of the harmonic components.
An a.c. voltage, V, comprises of a fundamental voltage of 100 V rms at a frequency of 120 Hz, a 3rd harmonic which is 20% of the fundamental, a 5th harmonic which is 10% of the fundamental and at a phase angle of 1.2 radians lagging.
(i) Write down an expression for the voltage waveform.
(ii) Sk READ MORE »
For the waveform shown in attached figure, estimate
(a) the damping factor,
(b) the forced or damped frequency of oscillation, and
(c) the natural or undamped frequency.
 What concepts would you use to describe the asteroid's motion?
 If the asteroid is moving at a constant speed in its orbit, does this also mean it is moving at a constant velocity? Explain your answer.
 Based on your answer above, is the asteroid accelerating? Explain.
 What force ac READ MORE »
(a) The circuit of FIGURE 2 (attached) is known as a trans-impedance circuit used for the measurement of very small currents. Derive the relationship between the output voltage V and the input current I; i.e. if V = kI find k in terms of R1, R2 and Rf.
(b) Calculate the current I if Rf =10 mOhm ( READ MORE »