Download 6 - JustAnswer

6. If F1=50lb upward and F2=60lb upward ,the resultant and the direction of the resultant along the
common line of action would be (A)10lb down (B)90lb up (C)110lb up (D)210lb up
7. A body that weighs 50lb is placed in contact with an inclined plane surface. The coefficient of friction
between the surfaces is 0.25 and the angle between the inclined surface and the horizontal reference
plane in 28 degrees. In order to keep the body from sliding, by using an applied force whose line of
action is parallel to the inclined supporting surface, what is the last permissible magnitude of force?
(A)6.3lb (B)12.5 (C)14 (D)50
8. The condition that must exist when a body is at rest is that the magnitude of the resultant of forces
acting on the body must be (A)0. (B)20 percent (C)dependent upon the incline (D)external
9. When solving a practical problem where the magnitudes of two forces are unknown, your calculations
can be simplified if one of the reference axes coincides with the line of action of one the unknown forces
and the other reference axis is (a)equal zero (B)horizontal to that line of action (C)perpendicular to that
line of action (D)vertical to that line of action
10. What will be the result when the applied horizontal force and the friction force form a couple, the
lines of action are parallel, and the magnitude are equal? They will (A)act in the same direction (B)cause
the body to rotate (C)create a mutual force (D)create friction
11. A body that weighs 50lbs is placed in contact with an inclined plane surface. The coefficient of
friction between the surfaces in contact is 0.25. If the angle between the inclined surface and a
horizontal reference plane is 28 degrees and if the body is to be prevented from sliding by and applied
force whose line of action is parallel to the inclined supporting surface,what is the least permissible
magnitude of (A)1.25lb (B)12.5 (C)125 (D)0.125
12. A body that weighs 50lbs is paced in contact with an inclined plane surface. The coefficient of friction
between the surfaces in contact is 0.25. If the angle between the inclined surface and a horizontal
reference plane is 28 degrees,what would be the angle of repose for the body and the material used for
the surface? (A)14degrees 00’ (B)17 00’ (C)20 00’ (D)30 00’
13. A wheel whose radius is 27in. was rotating with a uniform angular velocity equal to 4rpm. The
magnitude of the linear velocity of a particle on the circumference of the wheel in feet per was
(A)0.94fps (B)3.77fps (C)7.54 (D)11.31
14. A baseball was thrown vertically upward from a point 6ft above the ground with an intial velocity
whose magnitude was 120fps.When the ball reached the highest point on its path,what was the vertical
distance from the point from which it was thrown? (A)120ft (B)155 (C)190 (D)224
15. A wheel whose radius is 30 in. was rotating with a uniform angular velocity equal to 3rpm. The
magnitude of he linear velocity of a particle on the circumference of the wheel in feet per second was
(a)0.523ps (B)0.785 (C)7.541 (D)11.317
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 53mph, the number of minutes needed to make the trip would be
(A)170 min (B)200min (C)225 (D)249
17. 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
accelerationshould be (A)0.5 rad per sec per sec (B)0.6 (C)0.7 (D)0.8
18. The radius of a wheel is 2.5ft. At a certain instant t1, 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 t2
which was 2 sec later than t1, the magnitude of the tangential component of the linear acceleration of a
particle on the circumference of the wheel was (A)0.50fps per sec (B)0.6 (C)0.7 (d)0.8
19. What is the displacement vector for a body that moved from a position of 6ft to the left of a
reference point to a position of 10ft to the right of the reference point? (A)10ft to the left (B)12 ft to the
right (C)18ft to the right (D)22ft to the left
20. 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?(A)-0.00125rps per sec (B)-0.0125 (C)-0.1250 (D)1.250
21. 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 second? (A)45rev (B)60 (C)90 (D)113
22. A man holds a rifle in a horizontal position 4ft 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)250ft (B)500 (C)1000ft
(D)1280
23. As a line in a body rotates, the value of the angle that this line makes with fixed reference line
(A)continually increases (B)continually decreases (C)remains constant (D)varies by 30 degrees
24. 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)15fps
(B)22.8 (C)28.2 (D)880fps
25. To analyze the movement of a particle on a rotating line, will need to consider the relationship
between the (A)angular motion and the curvilinear translation (B)constant distance and the stationary
particle (C)constant distance and the angular motion (D)tangential component and the displaced vector
26. An automobile traveled along a highway with a mean velocity equal to 55mph. The distance covered
in 45 min was (A)22.50miles (B)31.75 (C)41.25 (D)51.00
27. A solid sphere whose diameter is 3.5ft weighs 600lb. The mass moment of inertia of the sphere with
respect to a horizontal line through its center of gravity is (A)22.8 slug ft2 (B)28.5 slug ft2 (C)36.0 slug ft2
(D)45.6 slug ft2
28. A truck with a velocity of 35 mph is traveling along a horizontal stretch of highway. If the total weight
of the truck and its contents is 8400lb, the magnitude of the linear momentum of the truck is (a)9150lbsec (B)11,259 (C)13,390 (D)18,300
29. A spring has a normal length equal to 15in.and the constant for it is 4lb per in. One end of the spring
is attached to a stationary support, and the other end of the spring is attached to a movable black which
can only travel along a straight horizontal path. After the block had been moved so that the length of
the spring was reduced to 10in.,the force that was applied to the block to cause this movement was
taken away and the spring was permitted to return to its original length. The amount of work done by
the spring in bringing the block back to its original starting position was (A)50 in-lb (B)125 in-lb (C)175
(D)250
30. An automobile weighing 3220lb and having a uniform linear velocity of 55 mph was traveling along a
curved portion of a highway. If the radius of the curve was 600ft, the magnitude of the centrifugal force
was (A)503lb (B)650 (C)872 (D)1085.
31. When a body is rotating under the action of a system of forces and the resultant moment of all
forces does not change, the body is subjected to an (A)axis of rotation (B)centripetal force (C)mass
moment of inertia (D)uniform angular acceleration
32. A solid wheel is being rolled toward the right along a horizontal surface by a force whose line of
action is horizontal. The diameter of the wheel is 2.5ft, the wheel weighs 80lb, and the magnitude of the
force is 15 lb. If the friction force is sufficient to prevent slipping of the wheel on the supporting surface,
the magnitude of linear acceleration of the center of gravity would be (A)3.22fps per sec (B)4.03 (C)5.15
(D)6.44
33. The radius of a cylindrical fly wheel is 2ft and the weight of the flywheel is 350lb.A force whose
magnitude is 40lb is applied to the rim the wheel along a line that is tangent to the rim. The magnitude
of the angular acceleration of the wheel would be (A)1.84 rad per sec per sec (B)2.25 (C)2.90 (D)3.69
34. An elevator car in a building is expected to move upward with an acceleration whose magnitude is
6fps per sec when the magnitude of the force that tends to lift the car is 4000lb. If the effect of friction is
neglected, the greatest total weight of the car and its contents can be (A)3000lb (B)3160 (C)3290
(D)3370
35. The force that acts toward the center of the circle along a radial line is known as (A)centrifugal force
(B)centripetal force (C)liner acceleration (D)linear velocity
36. The usual equation of motion for translation along a straight path is (A)A=mz (B)F=ma (C)Fx=ma
(D)triangle t=F
37. The normal length of a spring is 6in.,and the spring constant is 20lb per inch. How much work would
have to be done on the spring to reduce its length from 6in. to 4.6in? (A)12.2in.-lb (B)22.5 (C)32.5 (D)80
38. The diameter of a solid wheel is 3.5ft, and its weight is 60lb. The wheel is rolled toward the left along
a horizontal surface under the action of a horizontal force whose magnitude is 20lb. If the friction force
is sufficient to prevent slipping , what is the magnitude of the linear acceleration of the center of gravity
of the wheel? (A)3.21fps per sec (B)5.32 (C)7.16 (D)8.15
39. A body that is under the action of a system of forces moves along a straight path. One force of the
system has a constant magnitude equal to 200lb, and the angle between the line of action of this force
and the path of the moving body is 20 degree. If the body moved 3ft along its path during 5 sec, how
much work was done on the body by the specified force during that time interval? (A)269ft-lb (B)329
(C)435 (D)564
40. An automobile weighing 3600lb and having a uniform linear velocity of 50 mph was traveling along a
curved portion of highway. If the radius of the curve was 720ft, the magnitude of the centrifugal force
was (A)503lb (B)650 (C)835 (D)872