PHYSICS 1301

(Sample) EXAM 1

Dr. Mills                                                                                Fall 2000

Answer 4 of the following questions for full credit on this exam. Show all your work. Circle the answer to each part of each problem you work. Work an additional problem as an extra-credit problem.

1. A model rocket is launched straight upward with an initial speed of 50 m/s. It accelerates with a constant acceleration of 2.0 m/s2 until its engine stops at an altitude of 150 m.  
(1) What is the maximum height reached by the rocket? (a) 102 m (b) 158 m (c) 308 m (d) 408 m (e) 508 m (2) How long after lift-off does the rocket reach its maximum height? (a) 1.24 s (b) 2.84 s (c) 5.68 s (d) 8.52 s (e) 10.55 s (3) How long is the rocket in the air? (a) 5.67 s (b) 7.93 s (c) 8.52 s (d) 10.45 s (e) 16.45 s (4) If the rocket has at the time the engines stop a lateral velocity of 3.5 m/s (which it accelerates to uniformly from time of launch) how far away from the launch site will the rocket travel? (a) 19.8 m (b) 27.8 m (c) 36.5 m (d) 47.6 m (e) 57.7 m
  2. A mass M2 is attached to the suspended mass M1 by a string and a pulley as shown in the figure. M2 is also attached to mass M3 on the inclined plane. The pulleys are massless and frictionless. Coefficients of friction are as shown. Determine (5) the tension T1 (a) 6.8 N (b) 16.2 N (c) 19.6 N (d) 23.0 N (e) 28.6 N (6) the tension T2 (a) 6.8 N (b) 16.2 N (c) 19.6 N (d) 23.0 N (e) 28.6 N (7) the direction of acceleration of mass M1? (a) up (b) down (c) doesn't move (d) sideways (e) I don't know (8) the magnitude of the acceleration. (a) 0 m/s2 (b) 1.2 m/s2 (c) 2.0 m/s2 (d) 2.7 m/s2 (e) 3.0 m/s2
  3. A polished granite block of mass 1 kg rests on a steel table and is connected by a light cord to a mass, M, and a wall as in the figure. Given that the angle t = 45o
     
      (9) what is the maximum value M can have before it and m begin to move?
       
          (a) 0.1 kg (b) 0.3 kg (c) 0.75 kg (d) 1.5 kg (e) 2.7 kg
      (10) Would your answer be different if the apparatus were placed on Mars?
          (a) Yes (b) No (c) maybe (d) when it rains (e) none of these!
      (11) Explain why!! (write a paragraph) Assume that the kinetic coefficient of friction is 0.200 and the static coefficient of friction is 0.300 for polished granite against steel

     
     
     

    Prob 3 figure:

    4. A glider is towed by a single engine airplane. The tow rope makes an angle of 30o to the horizontal. If the tow plane pulls on the rope with a force of 5000 N at it’s highest attainable altitude before releasing the glider and the glider does not move up or down,

(12) what is the weight of the glider? (a) 441 kg (b) 225 kg (c) 2500 N (d) 5000 N (e) 4300 N (13) What is the horizontal acceleration? (a) 0 m/s2 (b) 9.8 m/s2 (c) 16.9 m/s2 (d) 19.6 m/s2 (e) 22.7 m/s2 (14) if wind resistance provides a retarding force proportional to the velocity of the glider where the constant of proportionality, k, is 100 kg/s (i.e. air friction is = kv), what is the maximum speed before the glider is released? (a) 16.8 m/s (b) 22.7 m/s (c) 31.5 m/s (d) 43.0 m/s (e) 52.1 m/s 5. Batman chases the Joker off a cliff. If Batman starts accelerating at 15 m/s2 from a stop to try and catch the Joker who is traveling at a constant velocity and both start 100 m from the edge of the 100 m high cliff: (15) How fast must the Joker be traveling in order for Batman to just not quite catch him before he goes over the edge of the cliff? (a) 6.67 m/s (b) 10.4 m/s (c) 18.75 m/s (d) 27.4 m/s (e) 38.7 m/s (16) How far will Batman go if he continues to accelerate horizontally before he hits the ground below the cliff? (a) 75 m (b) 102 m (c) 124 m (d) 277 m (e) 560 m (17) What is his speed (magnitude of velocity) when he hits the ground? (a) 35 m/s (b) 44 m/s (c) 123 m/s (d) 130 m/s (e) 152 m/s (18) At what angle is he traveling (relative to horizontal) when he hits the ground at the base of the cliff? (a) -10o (b) -15o (c) -20o (d) -30o (e) -40o


6. A projectile is fired up an inclined plane which is angle f to the horizontal with an initial velocity of Vo at an angle do with respect to the horizontal (do > f). Show that the projectile will travel a distance d up the inclined plane where:
    d = 2 Vo2 cos do sin (do – f) / [g cos2 f] Quantities you may need to use on this test – if you need others ask me!!
    g is the acceleration of gravity on the earth (9.8 m/s2) G = 6.67 x 10-11 Nm2/kg2