# Online Engineering Mechanics Test - Engineering Mechanics Test 5

Instruction:

• This is a FREE online test. DO NOT pay money to anyone to attend this test.
• Total number of questions : 20.
• Time alloted : 30 minutes.
• Each question carry 1 mark, no negative marks.
• DO NOT refresh the page.
• All the best :-).

1.

Determine the magnitude and direction of the resultant force.

A.
 R = 80.3 lb, = 106.2° CCW
B.
 R = 80.3 lb, = 73.8° CCW
C.
 R = 72.1 lb, = 63.6° CCW
D.
 R = 72.1 lb, = 116.4° CCW

2.

Determine the angle between the pole AC and the wire AB.

A.
 = 131.8°
B.
 = 70.5°
C.
 = 109.5°
D.
 = 48.2°

3.

Determine the moment of force F1 about point A on the beam.

A.
 M1 = 1600 ft-lb
B.
 M1 = 100 ft-lb
C.
 M1 = 100 ft-lb
D.
 M1 = 1600 ft-lb

4.

Determine the moment of the force at A about point P. Use a vector analysis and express the result in Cartesian vector form.

A.
 MP = (160i+240j+40k) N-m
B.
 MP = (380i+160j+400k) N-m
C.
 MP = (280i+200j+400k) N-m
D.
 MP = (40i+80k) N-m

5.

Determine the tension in the supporting cables BC and BD and the components of reaction at the ball-and-socket joint A of the boom. The boom supports a drum having a weight of 200 lb. at F. Points C and D lie in the x—y plane.

A.
 Ax = 0, Ay = 150 lb, Az = 562 lb, TBC = 300 lb, TBD = 212 lb
B.
 Ax = 0, Ay = 150 lb, Az = 456 lb, TBC = 150 lb, TBD = 212 lb
C.
 Ax = 0, Ay = 267 lb, Az = 843 lb, TBC = 533 lb, TBD = lb
D.
 Ax = 0, Ay = 150 lb, Az = 500 lb, TBC = 212 lb, TBD = 212 lb

6.

The flying boom B is used with a crane to position construction materials in coves and underhangs. The horizontal "balance" of the boom is controlled by a 250-kg block D, which has a center of gravity at G and moves by internal sensing devices along the bottom flange F of the beam. Determine the position x of the block when the boom is used to lift the stone S, which has a mass of 60 kg. The boom is uniform and has a mass of 80 kg.

A.
 x = 2.500 m
B.
 x = 0.340 m
C.
 x = 1.180 m
D.
 x = 0.600 m

7.

The floor beams AB and BC are stiffened using the two tie rods CD and AD. Determine the force along each rod. Assume the three contacting members at B are smooth and the joints at A, C, and D are pins.

A.
 T = 480 lb
B.
 T = 520 lb
C.
 T = 1248 lb
D.
 T = 1152 lb

8.

The Warren truss is used to support a staircase. Determine the force in members CE, ED, and DF, and state whether the members are in tension or compression. Assume all joints are pinned.

A.
 ED = 3.60 kN T, DF = 1.70 kN C, CE = 6.22 kN C
B.
 ED = 2.00 kN C, DF = 2.26 kN C, CE = 2.26 kN T
C.
 ED = 0.800 kN C, DF = 1.131 kN T, CE = 2.83 kN C
D.
 ED = 0.400 kN C, DF = 2.26 kN T, CE = 4.53 kN C

9.

The jack shown supports a 350-kg automobile engine. Determine the compression in the hydraulic cylinder C and the magnitude of force that pin B exerts on the horizontal member BDE.

A.
 FC = 8.75 kN, FB = 5.43 kN
B.
 FC = 5.15 kN, FB = 5.15 kN
C.
 FC = 8.58 kN, FB = 5.15 kN
D.
 FC = 5.25 kN, FB = 7.36 kN

10.

Locate the center of gravity of the volume generated by revolving the shaded area about the z axis. The material is homogeneous.

A.
 = 2.80 ft
B.
 = 2.50 ft
C.
 = 2.67 ft
D.
 = 3.00 ft

11.

The v-s graph for a rocket sled is shown. Determine the acceleration of the sled when s = 100 m and s = 175 m.

A.
 a100 = 3.75 m/s2, a175 = -1.250 m/s2
B.
 a100 = 11.11 m/s2, a175 = -25.0 m/s2
C.
 a100 = 0.333 m/s2, a175 = -1.000 m/s2
D.
 a100 = 33.3 m/s2, a175 = -25 m/s2

12.

The pilot of flighter plane F is following 1.5 km behind the pilot of bomber B. Both planes are originally traveling at 120 m/s. In an effort to pass the bomber, the pilot in F gives his plane a constant acceleration of 12 m/s2. Determine the speed at which the pilot in the bomber sees the pilot of the fighter plane pass at the start of the passing operation the bomber is decelerating at 3 m/s2. Neglect the effect of any turning.

A.
 vF/B = 150 m/s
B.
 vF/B = 367 m/s
C.
 vF/B = 90 m/s
D.
 vF/B = 212 m/s

13.

A sled is traveling down along a curve which can be approximated by the parabola y = x2. When point B on the runner is coincident with point A on the curve (xA = 2m, yA = 1 m), the speed if B is measured as vB = 8 m/s and the increase in speed is dvB/dt = 4 m/s2. Determine the magnitude of the acceleration of point B at this instant.

A.
 a = 8.94 m/s2
B.
 a = 12.00 m/s2
C.
 a = 16.10 m/s2
D.
 a = 8.16 m/s2

14.

When the motorcyclist is at A he increases his speed along the vertical circular parth at the rate of v = (0.3t)ft/s2, where t is in seconds. If he starts from rest when he is at A, determine his velocity and acceleration when he reaches B.

A.
 v = 51.1 ft/s2, a = 9.83 ft/s2
B.
 v = 51.1 ft/s2, a = 8.18 ft/s2
C.
 v = 51.1 ft/s2, a = 10.31 ft/s2
D.
 v = 51.1 ft/s2, a = 8.69 ft/s2

15.

A car is traveling at a speed of 80 ft/s when the brakes are suddenly applied, causing a constant deceleration of 10 ft/s2. Determine the time required to stop the car and the distance traveled before stopping.

A.
 t = 8 s, s = 800 ft
B.
 t = 8 s, s = 320 ft
C.
 t = 4 s, s = 240 ft
D.
 t = 4 s, s = 40 ft

16.

A boy twirls a 15-lb bucket of water in a vertical circle. If the radius of curvature of the path is 4 ft, determine the minimum speed the bucket must have when it is overhead at A so no water spills out.

A.
 v = 11.35 ft/s
B.
 v = 0
C.
 v = 6.26 ft/s
D.
 v = 2.83 ft/s

17.

If the block at C is moving downward at 4 ft/s, determine the angular velocity of bar AB at the instant shown.

A.
B.
C.
 TAB = 0
D.

Learn more problems on : Planar Kinematics of a Rigid Body (PKRB)

18.

Arm ABCD is printed at B and undergoes reciprocating motion such that = (0.3 sin 4t) rad, where t is measured in seconds and the argument for the sine is in radiaus. Determine the largest speed of point A during the motion and the magnitude of the acceleration of point D at this instant.

A.
 vAmax = 0.0600 m/s, aD = 1.002 m/s2
B.
 vAmax = 0.300 m/s, aD = 0.960 m/s2
C.
 vAmax = 0.0600 m/s, aD = 0.916 m/s2
D.
 vAmax = 0.300 m/s, aD = 0.288 m/s2

Learn more problems on : Planar Kinematics of a Rigid Body (PKRB)

19.

The slender 200-kg beam is suspended by a cable at its end as shown. If a man pushes on its other end with a horizontal force of 30 N, determine the initial acceleration of its mass center G, the beam's angular acceleration, and the tension in the cable AB.

A.
 aG = 0, = 0.225 rad/s2, T = 1.962 kN
B.
 aG = 0.0750 m/s2, = 0.1125 rad/s2, T = 1.962 kN
C.
 aG = 0, = 0.1125 rad/s2, T = 1.962 kN
D.
 aG = 0.1500 m/s2, = 0.225 rad/s2, T = 1.962 kN

20.

A clown, mounted on stilts, loses his balance and falls backward from the position, where it is assumed the = 0 when = 07deg;. Paralyzed with fear, he remains rigid as he falls. His mass including the stilts is 80 kg, the mass center is at G, and the radius of gyration about G is kG = 1.2 m. Determine the coefficient of friction between his shoes and the ground at A if it is observed that slipping occurs when = 30°.

A.
 = 0.833
B.
 = 0.468
C.
 = 0.243
D.
 = 0.400