PHYSICS DEPARTMENT

PHY2004                         Exam #1                 Sept. 23, 1996
Stanton
NAME
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Use the following:
     g = 9.8 m/s2 = 32.2 ft/s2
     mass of earth = 6.0 x 1024 kg
     radius of earth = 6.4 x 103 km
     1 mile = 5280 ft
     G = 6.67 x 10-11 N-m2/kg2



    

  1. Vector A is 5 units long and directed along the positive y-axis. Vector
B is 7 units long and directed along the negative x-axis. Vector C is 10
units long and directed along the negative y-axis. What is the MAGNITUDE
of the vector, A+B-2C ? 
    

    

    2. 


      

    1. 26.0 units 
      2. 


    2. 8.0 units 
      3. 


    3. 16.6 units 
      4. 


    4. 8.6 units 
      5. 


    5. 2.0 units 
      6. 

    



    

    


  2. Vector A is 20 m long in the +x direction. Vector B is 10 m long in
the +y direction. What angle does the vector A-2B make with respect to
the +x direction (measured counterclockwise, as is the usual convention)?

    

    

    3. 


      

    1. 315o 
      2. 


    2. 45o 
      3. 


    3. 27o 
      4. 


    4. 333o 
      5. 


    5. 225o 
      6. 

    



    

    


  3. Vector A has magnitude 15 km and is in a direction 150o 
counterclockwise from the +x axis. What is the value for the x-component 
of A in km? 
    

    

    4. 


      

    1. -13 
      2. 


    2. 13 
      3. 


    3. 7.5 
      4. 


    4. -7.5 
      5. 


    5. -9.6 
      6. 

    



    

    


  4. * A car is moving due north at a speed of 10m/sec. It enters a curve
and ends up heading due west at a speed of 10m/sec. The change in velocity
vector, vf - vi, is in the _________________ direction.

    

    

    5. 


      

    1. SW 
      2. 


    2. NW 
      3. 


    3. NE 
      4. 


    4. SE 
      5. 


    5. S 
      6. 

    



    

    


  5. David Letterman stands on the roof of the CBS studio in New York. He
throws a watermelon with an intial velocity in the +y-direction (upwards)
of 15 feet/sec. It a takes 7.5 seconds for the watermelon to smash on the
pavement below. How tall, in feet, is the CBS studio? (neglect any air
friction). 
    

    

    6. 


      

    1. 793 
      2. 


    2. 1020 
      3. 


    3. 906 
      4. 


    4. 388 
      5. 


    5. 163 
      6. 

    



    

    


  6. A car is travelling down the road at a speed of 75 km/hr. A deer darts
in front of the car 200 m ahead. Assuming the driver applies the brakes
instantaneously, what is the minimum rate of deceleration in m/sec2
 so that the driver stops before hitting the deer? 
    

    

    7. 


      

    1. 1.1 
      2. 


    2. 14.1 
      3. 


    3. 2.2 
      4. 


    4. 7.1 
      5. 


    5. 9.8 
      6. 

    



    

    


  7. * A canonball is fired at a 37o degree angle. If the range
of the canonball is 1200m, then what is the intial velocity in m/sec that
the cannonball must have? (Neglect any air friction). 
    

    

    8. 


      

    1. 111 
      2. 


    2. 77 
      3. 


    3. 1.2X104 
      4. 


    4. 89 
      5. 


    5. 67 
      6. 

    



    

    


  8. A police car travelling along the highway at 60 miles/hr notices someone
speeding. The police car uniformly changes its velocity from 60 miles/hr
to 90 miles/hr in 5 seconds. What is the acceleration of the police car,
in ft/sec2 during this time? 
    

    

    9. 


      

    1. 8.8 
      2. 


    2. 6.0 
      3. 


    3. 18.0 
      4. 


    4. 26.4 
      5. 


    5. 12.0 
      6. 

    



    

    


  9. The mass of Planet X (newly discovered) is 6 times the mass of Earth
and its radius is 3 times the radius of Earth. What is the acceleration
due to gravity, gx, at the surface of Planet X in m/sec2?

    

    

    10. 


      

    1. 6.5 
      2. 


    2. 14.7 
      3. 


    3. 4.9 
      4. 


    4. 19.6 
      5. 


    5. 6.9 
      6. 

    



    

    


  10. Figure 1 shows a mass of 20 kg hanging from a rope inside an elevator
car. If the tension in the rope is 174 Newtons, then what is the magnitude
(in m/sec2) and direction of the acceleration of the elevator
car? 
    

    

    11. 


      

    1. 1.1 down 
      2. 


    2. 1.1 up 
      3. 


    3. 0 
      4. 


    4. 21 up 
      5. 


    5. 21 down 
      6. 

    



    

    


  11. A 2000 kg truck is moving at 20 m/s. It uniformly slows to a stop in
a distance of 100 m. What was the force, in Newton, of deceleration during
this time? 
    

    

    12. 


      

    1. 4000 
      2. 


    2. 800 
      3. 


    3. 8000 
      4. 


    4. 200 
      5. 


    5. 400 
      6. 

    



    

    


  12. The two blocks shown in figure 2, each have a mass of 1.6 kg. The tension
in the cord at the left is 5.0 N. What is the tension in the cord connecting
them in N? Neglect friction with the table. 
    

    

    13. 


      

    1. 2.5 
      2. 


    2. 5.0 
      3. 


    3. 0 
      4. 


    4. 15.7 
      5. 


    5. 8.0 
      6. 

    



    

    


  13. An ice skater with mass 55 kg, has an intial velocity of 5 m/sec. If
it takes 10 seconds for the skater to come to rest and the only force acting
on the skater is friction, then what is the coefficient of friction between
the ice skates and ice? 
    

    

    14. 


      

    1. 0.05 
      2. 


    2. 0.1 
      3. 


    3. 0.02 
      4. 


    4. 0.5 
      5. 


    5. 0.01 
      6. 

    



    

    


  14. A box of mass 10 kg slides down an inclined plane with angle 37o
(see figure 3). If the acceleration is 3.2 m/s2 down the
plane, then what is the frictional force in Newtons? 
    

    

    15. 


      

    1. 27 
      2. 


    2. 78 
      3. 


    3. 32 
      4. 


    4. 46 
      5. 


    5. 66 
      6. 

    



    

    


  15. * A 30 kg sled is being pushed on ice as shown in figure 4. If the
handle makes an angle of 40o with the ice, and the coefficient
of friction is 0.1, then how much force (in Newtons) must be directed along
the handle so the sled moves at a constant speed of 5 m/s? 
    

    

    16. 


      

    1. 42 
      2. 


    2. 35 
      3. 


    3. 52 
      4. 


    4. 38 
      5. 


    5. 46 
      6. 

    



    

    


  16. How large a force (in newtons) does it take to push a 25 kg box up
a 25o  incline at a constant velocity if the coefficient of friction
between the box and incline is 0.6? 
    

    

    17. 


      

    1. 237 
      2. 


    2. 284 
      3. 


    3. 104 
      4. 


    4. 133 
      5. 


    5. 30 
      6. 

    



    

    


  17. * A 150 lb sign is suspended from two cables as shown in figure 5.
What is the tension in lbs. in rope 1? 
    

    

    18. 


      

    1. 108 
      2. 


    2. 125 
      3. 


    3. 75 
      4. 


    4. 305 
      5. 


    5. 100 
      6. 

    



    

    


  18. Two children are sitting at the ends of a 6 m seesaw. The children
weigh 250 N and 300 N respectively. How far, in m, from the 250 N child,
should the pivot be placed if the seesaw is to be balanced? Assume that
the seesaw has no weight for this problem. 
    

    

    19. 


      

    1. 3.3 
      2. 


    2. 2.7 
      3. 


    3. 3.0 
      4. 


    4. 3.5 
      5. 


    5. 4.2 
      6. 

    



    

    


  19. How much horizontal force (in Newtons) is needed to pull an 8.0 N pendulum
ball aside until the pendulum cord makes an angle of 40o with
respect to the vertical as shown in figure 6? 
    

    

    20. 


      

    1. 6.7 
      2. 


    2. 9.5 
      3. 


    3. 5.1 
      4. 


    4. 6.1 
      5. 


    5. 2.9 
      6. 

    



    

    


  20. In figure 7, a massless rod is suspended from one end at a pivot point.
If F1 = 300 N, then what must be the value of F2
(in Newtons) so that the rod is in equilibrium? 
    

    

    21. 


      

    1. 1200 
      2. 


    2. 600 
      3. 


    3. 693 
      4. 


    4. 346 
      5. 


    5. 946 
      6.