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Exam 1 fall 99
1. A sphere with a radius of 1.7 cm has a volume of :
2. Let v = 2i +6j -3k. the magnitude of v is
.
3. Let A = 2i +6j -3k and B = 4i +2j +k. Then A B equals
4. In the diagram, A has magnitude 12 and B has magnitude 8, The x component of A + B is about
5. The coordinate of an object is given as a function of time by x = 4t 2 - 3t3 , where x is in meters and
t is in seconds. Its average acceleration over the interval from t = 0 to t = 2s is:
6. Starting at time t = 0, and object moves along a straight line with velocity in m/s given by
v(t) = 98 - 2t2 , where t is in seconds. When it momentarily stops its acceleration is:
7. A car, initially at rest , travels 20 m in 4 s along a straight line with constant acceleration. The acceleration of the car (in m/s2) is:
8. An object is thrown straight up from ground level with a speed of 50 m/s. If g = 10 m/s 2 its distance above ground level 1.0 sec
later is:
9 - 12 A ball is thrown from the origin at time t = 0 with an initial velocity of v0 = 22i +
31j (in SI units)
9. The magnitude of the initial velocity, in SI units is closest to:
10. The angle the initial velocity makes with the x-axis (in degrees), is closest to:
11. The value of y, when the time t = 2.5 sec, in SI units, is closest to:
12. The y component of the velocity of the ball , when time t = 5 s, in SI units, is closest to:
13. A particle moves with constant speed around the circle shown. When it is at point A its coordinates
are x = 0, y = 2m and its velocity is v = 4 i (in m/s). When it is at point B its velocity and acceleration are
respectively:
14. A stone is tied to a 0.5m string and whirled at a constant speed of 4.0 m/s in a vertical circle. Its acceleration in m/s2 at the top of
the circle is:
15. A 25-kg chair is pushed across a frictionless horizontal floor with a force of 20 N, directed 20 0 below the horizontal. The
acceleration of the chair is:
16. Two forces are applied to a 5.0-kg object: one is 6 N to the north and the other is 8 N to the west. The magnitude of the
acceleration of the object is:
17. A 700-kg elevator accelerates downward at 3.0 m/s2. The force exerted by the cable on the elevator is:
18. A 1-lb pendulum bob is held at an angle  from the vertical by a 2-lb horizontal force F as shown. The
tension in the string supporting the pendulum bob (in pounds) is:
19. A man weighing 160 lb is in an elevator that is accelerating upward at 16 ft/s 2. The force exerted on him
by the elevator floor (in pounds) is:
20. The blocks are connected by a string and pulley as shown. Assuming that the string and pulley are
massless, the magnitude of the acceleration of each block is: