Answers and Explanations

Review Questions

1. C
   A 3 followed by 8 zeros, or 3 multiplied by 10 eight times.
2. B
   Mass is measured in kilograms, length in meters, and time in seconds.
3. D
   The prefix milli means 10^–3.
4. D
   
5. A
   Slope equals rise over run, which in this case would be
6. C

   The total area can be calculated by adding the area bounded by 4(6 – 2) = 16 and the area of the triangle bounded by v = 4 to v = 8 and t = 6 and

   

   Thus, the total area is 16 + 8 = 24.

7. C
   Since the kinetic energy is proportional to the square of the velocity, plotting KE vs. v would produce a parabola.
8. E
   The cosine is defined as the ratio of the adjacent side to the hypotenuse.
9. B
   Mass has no direction associated with it and therefore is a scalar, not a vector.
10. A

    The two displacements represent the two legs of a right triangle. By the Pythagorean theorem, the hypotenuse is equal to

    
11. C
    The x-component of the vector is the side adjacent to the 30º angle and is found by (10 m) cos 30° = 8.7 m.
12. A

    The figure below shows that the two y-components add up to 20 m, which is the y-component of the resultant. The y-component of the resultant (20 m) is the opposite side to the 60° angle, and the magnitude of the resultant can be found by