### Mechanical Engineering Review Question: Mechanics (Computation)

Mathematics and Engineering Sciences coupled with Engineering Economy comprise 35% of the board exam rating. This is mandated by Republic Act 8495 or The Philippine Mechanical Engineering Act of 1998. With that in mind, I created practice questions for review in preparation for the upcoming 2nd Phase of Mechanical engineering Board Exam this October 2010. I have below some practice questions specifically on the topic, Engineering Mechanics. I hope it will help a bit specially to those who are self-reviewing.

1. A 20kg block is resting in a horizontal surface. Calculate the force required to move it if the coefficient of static and dynamic friction are 0.75 and 0.6 respectively.
a. 118 N
b. 147 N
c. 196 N
d. 132 N

2. A 100kg object is sliding over a surface with static and dynamic coefficient of friction values of 0.5 and 0.3 respectively. If the initial velocity of the object is 10m/s, how long will it travel before it completely stops?
a. 17 m
b. 10.2 m
c. 20.4 m
d. 34 m

3. A 1kg ball is tied at the end of a 1.5m long rope and then rotated at the speed of 100 RPM. Calculate the tension on the rope.
a. 263.2 N
b. 41 N
c. 16.7 N
d. 164.5 N

4. A bullet is fired vertically from a gun situated 2 m above the ground. If the initial speed of the bullet is 100m/s, how high will it travel before it starts falling? Assume negligible air resistance.
a. 509.7 m
b. 507.7 m
c. 501.7 m
d. 511.7 m

5. A missile is fired from North Korea and is targeted towards South Korea. If the distance between the two countries is 100km and the firing angle is 45 degrees, at what velocity should the missile be fired to reach its target? Assume negligible air resistance.
a. 1981m/s
b. 120 m/s
c. 991 m/s
d. 556 m/s

6. Calculate the polar moment of inertia of a 30 cm diameter circular board.
a. 25312.5 cm^3
b. 79521.6 cm^4
c. 12656 cm^3
d. 12656.5 cm^4

7. A 20mm thick, 50 cm in diameter wheel made of cast iron (density: 6.0kg/cu m) starts rotating from rest and in 1 minute, attained an angular speed of 200 RPM. Calculate the angular acceleration in rad/s2?

8. A 2kg ball starts rolling down from the top of a 100m-high hill towards the plains. Calculate the final speed of the ball when it reaches the foot of the hill. Assume negligible friction.
a. 31.3 m/s
b. 62.6 m/s
c. 14 m/s
d. 44.3 m/s

9. A 500kg car is moving around a 500 m radius road with 5 degrees banking. If the minimum friction between the tires and the road is 0.2 during rainy days, calculate the maximum speed limit.
a. 136 kph
b. 112 kph
c. 74 kph
d. 83 kph

10. A 2kg object with a velocity of 10m/s hits a 3kg object at rest, sticks with it and move together in the same direction. Find the resulting velocity.
a. 6 m/s
b. 5 m/s
c. 4m/s
d. 3m/s

Answers and solution will be posted after one week. Let me know if there's any concern with the question or the choices.

### PAST MECHANICAL BOARD EXAM QUESTION: Machine Design Set-1 (solutions and answers)

The following are the solutions and answers to MODIFIED PAST MECHANICAL BOARD EXAM QUESTION: Machine Design Set-1 posted on this blog last Saturday, November 14, 2009. Again, I want to stress out that most of the questions here are modified from its original form for the purpose of improving the question. Past Mechanical Engineering Board Exam Question Number 1 A 4 inches diameter short shaft carrying 2 pulleys close to the bearings transmits how much horsepower if the shaft makes 120 rpm. A.200HP               B. 199 HP C.198 HP               D. 202 HP P = (D3N )/38 -- for mula for short shafts from PSME code P = (4)3(120)/38 P= 202 HP Past Mechanical Engineering Board Exam Question Number 2 An instrument that measures the hardness of the work piece in terms of elasticity. a. Durometer b. Scleroscope c. Mohs's Scale d. Brinell Tester Source: Machinery’s Handbook

### SOLUTION TO MECHANICAL BOARD EXAM PROBLEMS: Power Set-1

Here are the solutions to board problems given at Power Subject Set-1. If you do not understand anything, feel free to write a comment voicing out your concern. I'm still looking for better ways to present my solution. I still don't know how to present equations and mathematical symbols with blogger. Please bear with me. 1. An automobile tire is inflated to 32psig pressure at 50 degree F. After being driven, the temperature rises to 75 degree F. Determine the final gage pressure assuming the volume remains constant. (Electrical Engineering Board Exam Problem) Solution: Since volume is constant, use Charles’ Law on constant volume processes. P1/T1=P2/T2 Note: P and T should be absolute. (32+14.7)/ (50+460) =P2/ (75+460) P2=48.99 psia Converting back to gage pressure, P2g=48.99-14.7 P2g=34.29 psig 2. Four hundred cubic centimeters of gas at a pressure of 740 mmHg absolute and temperature of 18 degree C undergoes a process until the pressure and temperature be

### BOARD EXAM TIP: Which Review Center?

First of all, I would like to apologize for a long time I haven't posted anything but introduction. The reason for that is I'm busy optimizing the design of this site. I'm hoping that the make over is good. Anyway, I would like to dedicate this article to those who are going to take/retake the board exam this coming October. My sincere wish that you bring out the best among yourselves and may the deserving ones pass the exam. Going back to the One-Million-Peso worth question: "Which review center should I enroll?" , I would like to answer that in the most unbiased way I can. Of course, I'm only human and I had also my preferences but I will try my best to hide it. To start with I will enumerate some of the prominent review centers that offer board exam reviews for mechanical engineering in the Philippines. 1. Alcorcon (Cebu & Manila) 2. Excel (Cebu & Manila) 3. Linx Engineering (Manila) 4. MERIT (Manila) 5. PRIME (Cebu) 6. RLB's