PET8
1. How long does it take to dial the number 680-1725 using pulse dialing having an interdigit duration of 0.4 second?
(680-1725)d= 6+8+10+1+7+2+5=39 t= d(0.1) +(n-1)t in in
23. Benjo bought a lot worth P1,000,000 if paid in cash. On the installment basis, he paid a down payment of P200,000; P300,000 at the end of one year; P400,000 at the end of three years and a final payment at the end of five years. What was the final payment if the interest was 20%?
t= 39(0.1) +(7-1)(0.4) t= 6.3 sec. 7. What is the bandwidth of a QPSK signal if the bit rate is 6Mbps?
=
= 3MHz
P800,000 = P300,000(1+0.20)-1 + P400,000(1+0.20)-3 + X(1+0.20)-5 SHIFT>SOLVE for X
B = 3MHz NOTE: N=
Let: X be the FINAL payment and today as the focal date
for QPSK; BAUD RATE = BANDWIDTH
18. A piston cylinder device contains a liquid-vapor mixture of water at 400K. During a constant pressure process, 700KJ of heat is transferred to the water. As a result, part of the liquid in the cylinder vaporizes. Determine the entropy change of the water during the process.
=
JK
19. An electric heater warms a large block of ice at a rate of 200 joules per second. Calculate how much is the mass of ice that is melt in 10 minutes?
X = P792,576
–
NOTE: (P/F, i%, n) P= F(1 i) – n 24. A closed vessel contains air at a pressure of 160kN/m^2 gauge and temperature of 30 deg Celsius. The air is heated at constant volume to 60 deg Celsius with the atmospheric pressure of 759mmHg. What is the final gauge pressure?
= = SHIFT>SOLVE for X the final gauge pressure
≈ 86 kPa
Q= mHf
X = 185.86kPag
) 0.2 = m (334 ) ) ( ) (10min) m= (
NOTE: always convert to absolute pressure & tempt.
200 = m (334
m= 0.36 kg
(4.186 )( 1000 )
NOTE: Hf = 80
20. Sexy Lucille bought a car for P220,000 and used it for 10 years, the life span of the car. What is the book value of the car after 5 years of use? Assume a scrap value of P20,000 for the double declining balance method.
P220,000 C = P72,0896 ≈ P72,090 Cn= Co
=
5
21. A machine costing P720,000 is estimated to have a book value of P40,545.73 when retired at the end of 10 years. Depreciation cost is computed using a constant percentage of declining book value. What is the annual rate of depreciation in %?
k= 1-
√
= 1-
k= 0.25 = 25%
√
g
˚C 28Jg ˚C
25. A 3.0 grams bullet of specific heat 0.0305 cal/gis moving at 180m/s and enter a bag of sand then stops. If all kinetic energy is converted into heat, by what amount is the increase in temperature of the bullet?
KE = Q
8 =(1) (28 )T HIF>OLVE for
T = 126.56 ≈ 2 NOTE: proportionality constant = 1
27. A 2.53kJ of heat is absorbed by an ideal gas that occupies a volume of 22.4 liters at STP. If the gas expands isobarically to 32.4 liters, compute the change in the internal energy of the gas.
W PV
)
W = (101.325kPa)(32.4L-22.4L)( W = 1.01325 kJ The first law of thermodynamics:
Q W + U U U= 1.51675kJ ≈ .52kJ
2.53kJ = 1.01325kJ +
29. You need P4,000 per year for four years to go to college. Your father invested P5,000 in a 7% account for your college education when you were born. If you withdraw the P4,000 at the end of your 17 th, 18 th, 19 th, and 20th years, how much money will be left in the account at the end of 21 st year?
Let: 21st year be the focal date and X be the money left
P5,000(1+0.07)21 = P4,000( X = P1700
(1+0.07) +X
30. Lucille and Romar borrowed at the bank P2,000,000 for six years at 7% for their wedding. At the end of six years, they renew the loan for the amount due plus P1,000,000 more for four years at 7% in fulfillment of their dream house. What is the lump sum?
Let: F be the lump sum amount.
F = [P2,000,000(1+0.07)6 + P1,000,000](1+0.07)4 F = P5,245,098.73
