Physics 101.001                                 Final - Answers                              May 16, 2001

 

Read each question and its set of answers very carefully.  There is only one best answer for each question.  Don’t be afraid to ask questions of me during the exam.  Just raise your hand if you have one.

 

   1.  How many vibrations per second are represented in a radio wave of 101 MHz?

(a) 101                                           

(b) 101,000

(c) 101,000,000                             

(d) 1.01

 

   2.  An oceanic depth‑sounding vessel surveys the ocean bottom with ultrasonic sound that travels 1530 m/s in seawater.  Find the depth in meters of the water if the time delay of the echo from the ocean floor is 6s.

(a) 1530                                         

(b) 4590

(c) 9180                                         

(d) 1530/6

 

   3.  When successive impulses are applied to a vibrating object in time with the natural frequency of the object

(a) reverberation occurs             

(b) resonance occurs

(c) refraction occurs                   

(d) none of the above

 

   4.  The distinguishing difference in sound produced when a piano and a trumpet play the same note is called

(a) forced resonance                   

(b) beats

(c) fundamental difference         

(d) timbre

 

   5.  The moon must be in which phase for a solar eclipse to occur?

(a) lunar                                        

(b) full

(c) new                                          

(d) first quarter

(e) third quarter 

 

   6.  The colored dots that make up the color on a TV screen are

(a) red, blue, yellow                    

(b) red, blue, green

(c) yellow, blue, green                

(d) magenta, cyan, yellow

(e) red, green, yellow

 

   7.  You are 6 ft tall.  What minimum length mirror is required to see a full image of yourself? 

(a) 2 ft                                            

(b) 3 ft

(c) 6 ft

 

   8.  Optical fibers (light pipes) use which of the following principles to explain their operation? 

(a) refraction                                

(b) polarization

(c) reflection                 

(d) diffraction

(e) scattering

 

   9.  Two polaroids that have their polarization axes at 45o to each other will still allow light to pass through. 

(a) True                                         

(b) False

 

10.  Which is hottest? 

(a) a red hot object                      

(b) a blue hot object

(c) a white hot object

 

11.  How much speed does an object pick up in 2 seconds when it is undergoing a constant acceleration of 2 m/s2 in a straight line?

(a) 2 m/s                                        

(b) 4 m/s

(c) 2 m/s2                                                           

(d) 4 m/s2

 

12.  A projectile in the absence of air resistance can reach a range of 1000 ft when fired at an angle of 56 o.  For the same initial speed what other angle will give this same range?

(a) 44 o

(b) 45 o

(c) no other angle will work since 56 o is greater than 45 o

(d) 34 o

(e) none of the above

 

13.  Consider two identical bricks, one on the moon, one on the earth.  What do they have in common? 

(a) same inertia                            

(b) same weight

(c) same mass                              

(d) all of the above

(e) only (a) and (c) 

 

14.  A 10 N force causes an object to have an acceleration of 5 m/s2.  What acceleration in m/s2 will the object have if the force is doubled? 

(a) 5                                               

(b) 10

(c) 20                                             

(d) 5/2

(e) 5/4

 

15.  A Mack truck and a Volkswagen have a head‑on collision.  Which driver experiences the greater force?

(a) Mack truck driver

(b) Volkswagen driver

(c) both experience the same force

 

16.  If you push on an immovable wall for an hour, is there any work done on the wall?

(a) Yes                                           

(b) No

 

17.  A 10 lb weight is lifted 5 ft.  A 20 lb weight is lifted 2.5 ft.  Which lifting required the most work?

(a) 20 lb weight

(b) 10 lb weight

(c) same work for each lifting

(d) not enough information is given to work the problem

 

18.  Power is a measure of

(a) the amount of energy done

(b) the amount of work used

(c) the direction in which work is done

(d) the rate at which work is done

(e) the change in force per unit time

 

19.  The net or total work necessary to bring an object from zero velocity to its present nonzero velocity is equal to the                                               of the object.

(a) kinetic energy                        

(b) potential energy

(c) momentum                              

(d) force

(e) impulse

 

20.  What kind of energy is the energy in a coiled spring?

(a) potential                                  

(b) kinetic

 

21.  If a machine performs 100 ftilb of output work and is 20% efficient, how much energy input does the machine require?

(a) 500 ftilb                                  

(b) 2000 ftilb

(c) 20 ftilb                                    

(d) 100 ftilb

(e) none of the above

 

22.  How does a long pole help a tightrope walker to balance himself?

(a) the pole can be rotated rapidly to achieve balance

(b) the pole increases his torque

(c) the pole increases his rotational inertia

(d) the pole makes the man heavier

(e) it doesn't help

 

23.  In class which of the two red rods had the larger rotational inertia?

(a) the one with the mass at the ends

(b) the one with the mass at the center

(c) the one with the small moment of inertia

(d) they both had the same rotational inertia

(e) both had zero rotational inertia

 

24.  An unbalanced torque on an object will cause the object to

(a) move at a constant speed

(b) rotate at a constant angular acceleration

(c) rotate at a constant angular velocity

(d) accelerate

(e) torquate

 

25.  The center of mass of a pole vaulter can actually pass under the bar as the pole vaulter passes over the bar.

(a) True                                         

(b) False

 

26.  If you are riding on a merry-go-round at a constant angular velocity, what is the direction of the net force on you?

(a) the net force is zero

(b) toward the center of the merry-go-round

(c) tangent to the circle you are moving in

27.  What is required to change the angular momentum of a system?

(a) an impulse                              

(b) a jerk

(c) a spin                                       

(d) a force

(e) a torque

 

28.  What is the angular momentum of a 6 kg mass traveling with a speed of 6 m/s in a circle of radius of 12 m?

(a) 144 kgim2/s                            

(b) 36 kgim2/s

(c) 12 kgim2/s                              

(d) 432 kgim2/s

(e) 24 kgim2/s

 

29.  When a spinning ice skater draws her arms in close to her body, she starts to spin faster.  This is an example of

(a) momentum interchange

(b) spin impulse

(c) Newton's second law c

(d) conservation of angular momentum

(e) external torque friction

 

30.  Make the best association.  Copernicus and                 , Brahe and                 , Kepler and                 .

(a) observatory, heliocentric, ellipse

(b) ellipse, observatory, heliocentric

(c) observatory, ellipse, heliocentric

(d) heliocentric, observatory, ellipse

 

31.  If somehow the moon were moved to a distance half as far away from the earth as it is now, the force that the earth has for the moon would

(a) be one fourth as much as it is now

(b) be four times greater than it is now

(c) be one half of what it is now

(d) be twice what it is now

 

32.  What must be the phase of the moon if spring tides are occurring?

(a) waxing gibbous

(b) third quarter (last quarter)

(c) first quarter

(d) full

 

33.  What will determine whether the universe will expand forever or will halt expansion and collapse to the big crunch?

(a) the temperature of the universe

(b) how many black holes are in the universe

(c) the boundary of the universe

(d) the mass of the universe