Ch. 20 Homework, pt. 3 Begin Date: 3/5/2018 2:00:00 PM- Due Date: 3/7/2018 5:00:
ID: 1583361 • Letter: C
Question
Ch. 20 Homework, pt. 3 Begin Date: 3/5/2018 2:00:00 PM- Due Date: 3/7/2018 5:00:00 PM End Date: 3/9/2018 9:59:00 AM (33%) Problem 2: A large research solenoid has a self-inductance of 4.5 H. Randomized Variables L=4.5 H I=85 A t=65ms 33% Part (a) what is the magnitude of the emf, in kilovol ts, that opposes shutting off a current of 85 A through the solenoid, in 65 ms? Grade Summary Deductions Potential 100% = 0% sin0 cosO cotan inacos) atan acotansinh0 cosh0tanhcotanh( o Degrees Radians tan() | | ( ) | 7 | 8 | 9 4 5 6 *1 2 3 Submissions Attempts remaining: 6 (4% per attempt) a detailed view VO BACKSPACE DELCLEAR Submit Hint I give up! ac Hints: 1s% deduction per hint. Hints remaining: 2 Feedback: 1% deduction per feedback. 33% Part (b) How much energy in Joules is stored in the inductor at full current? 33% Part (c) At what rate in megawatts, must energy be dissipated when the full current is switched off in 65 ms?Explanation / Answer
a) E = L* di/dt = 4.5*85/65e-3 = 5885 V
b) energy stored = 0.5Li^2 = 0.5*4.5*85^2 = 16256 J
c) rate = energy/time = 16256/65e-3 = 0.25e6 W = 0.25 MW