Engineering Mechanics II
Practice Exam #2
Planar Constant Angular Acceleration & Dependent Motion
1.
Wheel B has radius RB = 20 cm and is initially rotating at 20
RPM while undergoing a constant angular acceleration of =10
rad/s2 in the same direction. How fast is it rotating at the end of
the 5 seconds? How many revolutions does it make in the 5
seconds? Point P is on wheel B at a distance of 15 cm from the
center. What is the total acceleration vector of point P at the
end of 5 seconds? Wheel A , which has radius R A=10 cm,
contacts wheel B at point C with no slipping. What is the initial
angular speed of wheel A?
Conservation of Energy
2.
At the instant shown, the 50-lb bar is rotating downwards at
2 rad/s. The spring attached to its end always remains
vertical due to the roller guide at C. If the spring has an
unstretched length of 2 ft and a stiffness of k=6 lb/ft,
determine the angular velocity of the bar the instant it has
rotated downward 30 degrees below the horizontal.
Principal of Work and Energy
3.
The elevator car E has a mass of 1.80 Mg and the counterweight C has a mass of
2.30 Mg. If a motor turns the driving wheel A with a torque of M=15 N*m, where 
is in radians, determine the speed of the elevator when it has ascended 14 m starting
from rest. Each wheel A and B has a mass of 150 kg and a radius of gyration of
k=0.2 m about its mass center at the axle. Neglect the mass of the cable and assume
the cable does not slip on the wheels.
MAE-2104
1
Ver. C, Rev 1
Engineering Mechanics II
Practice Exam #2
Linked Planar Velocity and Acceleration
4.
At a given instant, the slider block B is traveling to the right
with the velocity and acceleration shown. Determine the
angular speed and acceleration of the 5 inch radius wheel at
this instant.
Planar Rotating Reference Frames
5.
Arm AB has length RAB =0.12 meter. It is rotating clockwise at a rate
of A=2 rad/s that is increasing at A=3 rad/s2, and it is horizontal at
the instant shown. Arm BC has length RBC = 0.09 meter. Collar C has
a speed measured relative to arm BC of 4 m/s downward along arm
BC, and is accelerating at 5 m/s2 downward, also measured relative to
BC. Find the inertial velocity and acceleration of collar C at this
instant.
Planar Kinetics: Newton’s Law
6.
Determine the acceleration of the center of mass of the cylinder at the instant
shown. The tension in the rope is 12 N. The cylinder has a mass of 4 kg, and a
radius of 0.02 m. Assume the cylinder does not slip as it rolls.
MAE-2104
2
Ver. C, Rev 1