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Exam: 286038RR – Engineering Mechanics, Part 3

1. A wheel whose radius is 1.5 was rolling without slipping along a horizontal surface. At a certain instant, (see Examination Figure 2), the angular velocity of the wheel was 2.5 rad per sec. counterclockwise and the angular acceleration was 3 rad per sec per sec clockwise. At the instant specified the magnitude of the vertical component of the linear acceleration of the particle at the point B was

A. 9.0 fps per sec.

B. 4.50 fps per sec.

C. 5.50 fps per sec.

D. 7.50 fps per sec.

2. A baseball was thrown vertically upward from a point 6 ft above the ground with an initial velocity whose magnitude was 120 fps. When the ball reached the highest point on its path, what was the vertical distance from the point from which it was thrown?

A. 190 ft

B. 224 ft

C. 155 ft

D. 120 ft

3. A gas engine has a flywheel that rotates with a uniform angular velocity equal to 150 rpm. How many revolutions will the flywheel make in 45 seconds?

A. 45 rev

B. 60 rev

C. 113 rev

D. 90 rev

4. A wheel whose radius is 30 in. was rotating with a uniform angular velocity equal to 3 rpm. The magnitude of the linear velocity of a particle on the circumference of the wheel in feet per second was

A. 11.317 fps.

B. 0.523 fps.

C. 0.785 fps.

D. 7.541 fps.

5. During a race, an automobile was driven around a track having the shape shown in Examination Figure 1. If the automobile traveled a total distance equal to 450 miles in 3 hr 24 min, the magnitude of the mean velocity in miles per hour was

A. 132.4 mph.

B. 148.0 mph.

C. 125.0 mph.

D. 138.9 mph.

6. If the velocity of an automobile is 45 mph, the corresponding velocity in feet per second is A. 73.5 fps.

B. 66.0 fps.

C. 48.3 fps.

D. 30.7 fps.

7. What is the displacement vector for a body that moved from a position of 6 ft to the left of a reference point to a position of 10 ft to the right of the reference point?

A. 10 ft to the left

B. 22 ft to the left

C. 12 ft to the right

D. 16 ft to the right

8. A wheel whose radius is 1.5 ft was rolling without slipping along a horizontal surface. At a certain instant, as indicated in Examination Figure 2, the angular velocity of the wheel was 2.5 rad per sec counterclockwise and the angular acceleration was 3 rad per sec per sec counterclockwise. At the specified instant, the horizontal component of the linear velocity of a particle at the point A at the top of the wheel

(vertically above O) was

A. 1.40 fps to the right.

B. 3.75 fps to the right.

C. 7.50 fps to the left.

D. 5.50 fps to the left.

9. An automobile traveled along a highway with a mean velocity equal to 55 mph. The distance covered in 45 min was

A. 51.00 miles.

B. 22.50 miles.

C. 41.25 miles.

D. 31.75 miles.

10. A man holds a rifle in a horizontal position 4 feet above the ground and shoots the bullet with an initial velocity of 2000 fps horizontally. It may be assumed that the ground is level. What will be the horizontal distance from the man to the point at which the bullet strikes the ground?

A. 500 ft

B. 250 ft

C. 1280 ft

D. 1000 ft

11. A wheel whose radius is 27 in. was rotating with a uniform angular velocity equal to 4 rpm. The magnitude of the linear velocity of a particle on the circumference of the wheel in feet per second was

A. 3.77 fps.

B. 7.54 fps.

C. 0.94 fps.

D. 11.31 fps.

12. If the velocity of an automobile is 40 mph, the corresponding velocity in feet per second is A. 73.56 fps.

B. 58.68 fps.

C. 30.71 fps.

D. 48.32 fps.

13. A man rode a bicycle around a circular racetrack a specified number of times in such a way that the magnitude of his velocity remained practically constant. If he rode a total distance equal to 2 miles in 6 minutes and 15 seconds, what was the magnitude of the mean velocity in feet per second?

A. 15 fps

B. 880 fps

C. 28.2 fps

D. 22.8 fps

14. During normal operation, the angular velocity of the rotor of an electric generator is expected to be 5 rad per sec. Also, the rotor is expected to start from rest and to attain its normal angular velocity while it rotates through a total angle equal to 25 rad. The magnitude of the uniform angular acceleration should be

A. 0.5 rad per sec per sec.

B. 0.7 rad per sec per sec.

C. 0.8 rad per sec per sec.

D. 0.6 rad per sec per sec.

15. Assuming a flywheel rotates with a uniform angular velocity equal to 120 rpm, and that it was brought to rest in 16 seconds by reducing the angular velocity at a uniform rate, what was the required acceleration in revolutions per second per second?

A. -0.0125 rps per sec

B. -0.1250 rps per sec

C. -0.00125 rps per sec

D. 1.250 rps per sec

16. The distance between two cities along a railroad track is 150 miles. If the mean velocity of a train traveling between these cities is 53 mph, the number of minutes needed to make the trip would be

A. 249 min.

B. 200 min.

C. 170 min.

D. 225 min.

17. using the mechanism illustrated in Examination Figure 3, the collar has its maximum linear velocity when the crank is in a

A. stationary position.

B. horizontal position above the axle.

C. horizontal position below the axle.

D. vertical position above the axle.

18. To analyze the movement of a particle on a rotating line, you will need to consider the relationship between the

A. constant distance and the angular motion.

B. angular motion and the curvilinear translation.

C. constant distance and the stationary particle.

D. tangential component and the displaced vector.

19. The radius of a wheel is 2.5 ft. At a certain instant t

, the angular velocity of the wheel was 1.2 rad per

sec and there was a uniform angular acceleration equal to 0.3 rad per sec per sec. At an instant t 1, which was 2 sec later than t , the magnitude of the tangential component of the linear acceleration of a particle on the circumference of the wheel was

A. 0.75 fps per sec.

B. 0.50 fps per sec.

C. 1.50 fps per sec.

D. 1.00 fps per sec.

20. As a line in a body rotates, the value of the angle that this line makes with the fixed reference line

A. continually decreases.

B. remains constant.

C. continually increases.

D. varies by 30 degrees.