Physics 201 MWF10:20 Fall 1998 (Ford)
Final Exam Chapts. 1--17 in Cutnell and Johnson, 4th ed.
(10 pts) 1. A block with mass 0.030 kg is resting on a horizontal
frictionles surface and is attached to horizontal spring whose spring constant is 120 N/m. The block is then given a kick, that gives it an initial speed of 8.00 m/s, while the spring is initially unstretched. What is the amplitude of the resulting simple harmonic motion?
Ans.________________
(10 pts) 2. A thin rod has a length of 0.20 m and rotates in a circle on a frictionless tabletop. The axis is perpendicular to the length of the rod at one of its ends. The rod has an angular velocity of 0.50 rad/s and a moment of inertia for this axis of 1.2 × 10-3 kg·m2. A bug (mass = 5.0 × 10-3 kg) standing at the axis decides to crawl out to the other end of the rod. When the bug reaches the other end of the rod, what is the angular velocity of the rod?
Ans. _______________
(10 pts) 3. A small block with mass 0.2 kg is released from rest at point
A that is at the
top of a curved track. At point B at the bottom of the track, 5.0 m below A,
the block is observed to have a velocity of magnitude 6.0 m/s.
How much work was done by friction during the motion of the block
from point A to point B?
Ans. ________________
(8 pts) 4. In a cylinder 4 moles of an ideal gas at an initial temperature of
177°C expands until its volume is doubled (V2 = 2V1). For the gas
CV = 12.5 J/mol·K. The gas constant is R = 8.314 J/mol·K. If the expansion is carried out at constant
pressure, calculate
a) the work W done by the gas.
Ans. _________________
b) the change in internal energy 
U of the gas.
Ans. __________________
(12 pts) 5. A football kicked from ground level at a speed of
40 m/s and at an angle of 53° above the horizontal
strikes the wall of a tall building 4.0 s after being kicked.
a) What is the horizontal distance from the point where the football was kicked
to the base of the building?
Ans. __________________
b) What is the maximum height above ground reached by the ball during its
motion?
Ans. __________________
c) What is the magnitude of the velocity of the ball just before it strikes
the building?
Ans. __________________
(6 pts) 6. A source of sound waves approaches a stationary listener at a speed
of 20 m/s. The speed of sound in the air is 345 m/s.
If the listener hears a frequency of 240 Hz, what is the frequency emitted
by the source?
Ans. ___________________
(6 pts) 7. A string 1.6 m long is tied down at both ends. A certain
standing wave on the string has frequency 80 Hz and the next higher
frequency standing wave has frequency 100 Hz. What is the speed of
the transverse waves on the string?
Ans. __________________
(14 pts) 8. The system in the sketch is released from rest and the 20 kg
block moves downward while the other block moves up the incline. There
is no friction between the block and the incline. The pulley is massless
and frictionless. While the blocks are moving the tension in the rope is
90 N.
a) What is the magnitude of the acceleration of the 20 kg block?
Ans. _________________
b) What is the mass m of the block on the incline?
Ans. __________________
12 pts) 9. A small block with mass 0.020 kg slides without friction on
the circular track shown in the sketch. The block is released from rest
at point A, 14 m above the ground. Point B is at the top of a circular
section of the track that has radius R = 3.0 m.
a) What is the speed of the block as it passes through point B?
Ans. __________________
b) What is the magnitude of the downward normal force that the track
exerts on the block as it passes through point B?
Ans. ___________________
(12 pts) 10. A uniform bar weighing 120 N is attached at one end to a wall by a
frictionless hinge. The bar is held in a horizontal position by a cable that
makes an angle of 53° with the bar, as shown. What is
a) the tension in the cable?
Ans. ____________________
b) the horizontal and vertical components of the force the hinge exerts on
the bar?
Ans. horizontal ___________________
vertical_____________________