Name: ______Block: _____ Date: _____/_____/_____
Conceptual Physics
Chapter 3 Study Guide: Projectile Motion
Multiple Choice
Identify the choice that best completes the statement or answers the question. Write the letter of your response on the line provided.
____ 1. A scalar is a quantity that has _____.
a. / magnitude and time / c. / time a directionb. / magnitude and direction / d. / only a magnitude
____ 2. In order to find the components of a vector, you should _____.
a. / draw the vector with the correct magnitude and orientationb. / measure the sides of the right triangle
c. / draw a right triangle so that the vector is the hypotenuse
d. / all of the above
____ 3. In the absence of air resistance, the angle at which a thrown ball will go the farthest is _____.
a. / 15° / c. / 45°b. / 30° / d. / 60°
____ 4. A ball thrown in the air will never go as far as physics ideally would predict because _____.
a. / the ball would never land / c. / air resistance slows the ballb. / gravity is acting on it / d. / all of the above
____ 5. A cannonball is launched from the ground at 30 m/s at an angle of 30° above the horizontal. Ignoring air resistance, the ball with hit the ground with a speed of _____.
a. / 0 m/s / c. / 30 m/sb. / 20 m/s / d. / 9.8 m/s2
____ 6. A projectile launched horizontally hits the ground in 0.8 seconds. If it had been launched with twice the speed in the same direction, it would have hit the ground in _____.
a. / less than 0.8 sb. / twice the amount of time
c. / more than 0.8 s
d. / 0.8 s
____ 7. An object is dropped and falls freely to the ground with an acceleration of g. If it thrown upward at an angle instead, its acceleration would be _____
a. / less than g / c. / gb. / more than g / d. / zero
____ 8. Which best approximates the resultant of a pair of 6-unit vectors perpendicular to each other?
a. / 0 units / c. / 8 unitsb. / 6 units / d. / 12 units
____ 9. Which best approximates the resultant of a pair of 6-unit vectors parallel to each other?
a. / 0 units / c. / 8 unitsb. / 6 units / d. / 12 units
____ 10. What is the resultant of a 3-unit vector and a 4-unit vector at right angles to each other?
a. / 1 units / c. / 7 unitsb. / 5 units / d. / none of the above
____ 11. When in orbit, a satellite such as the Hubble telescope or the moon is _____.
a. / simply a projectile / c. / free from Earth’s gravityb. / not acceleration / d. / moving with constant velocity
____ 12. Suppose a small plane can fly at 170 km/h and that there is a tailwind of 60 km/h. How fast does the plane’s shadow move across the ground?
a. / 110 km/h / c. / 185 km/hb. / 170 km/h / d. / 230 km/h
____ 13. Ignoring air resistance, at what other angle will a thrown ball go the same distance as one thrown at an angle of 75°?
a. / 15° / c. / 80°b. / 65° / d. / 90°
____ 14. Ignoring air resistance, at what other angle will a thrown ball go the same distance as one thrown at an angle of 10°?
a. / 15° / c. / 80°b. / 65° / d. / 90°
____ 15. When calculating the resultant of two vectors pointed in opposite directions, _____.
a. / the magnitudes should be added / c. / the magnitudes should be multipliedb. / the magnitudes should be subtracted / d. / use the Pythagorean theorem
True/False
Indicate whether the statement is true or false. Write the letter of your response on the line provided.
____ 16. The vector sum is called the resultant.
____ 17. When adding two vectors at right angles, the resultant of the vectors is the algebraic sum of the two vectors.
____ 18. A ball will go farthest when thrown at a 45° angle.
____ 19. Any vector can be represented by two other vectors that are at right angles to each other.
____ 20. Time is an example of a vector quantity.
Numeric Response
Respond to each of the following problems in the space provided. Make sure your numerical responses include both a number and a unit.
21. A motorboat is driven across a river at 3.0 km/h at a right angle to the current, which is flowing at 10 km/h. Sketch a diagram of this problem labeling each vector, then calculate the resultant vector.
22. An airplane heads north at a speed of 230 km/h with a crosswind blowing from the west at 80 km/h. Sketch a diagram of this problem labeling each vector, then calculate the resultant vector.
Problem
23. An airplane flies at 295 km/h parallel to the direction of the wind. The wind speed is 40 km/h. What are the two possible speeds of the plane relative to the ground? Explain your answer.
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