Chapter 2 Study Guide Part 2

Vector Practice

1. A boy scout troop marches 10 km east, 5.0 km south, 4.0 km west, 3.0 km south, 6.0 km west, and 8.0 km north. What is their net displacement from their starting point? How far have they marched?


2. Draw the vector , 10 units long pointing due east, and graphically add to it the vector , 15 units long pointing northeast at 45 deg. Measure both the magnitude of the resultant and its direction.


3. While playing catch a young woman throws a ball. It leaves her hand 1.00 m above the ground, sails through the air, and strikes a building that is 5.00 m away from her. The ball hits the wall at a height of 13.0 m. What was the magnitude of its displacement from its launch point at the moment it struck the wall?


4. A Roman catapult fires a boulder with a launch speed of 20 m/s at an angle of 60 deg with the ground. What are the projectile's initial horizontal and vertical speeds?


5. A cannon is fired due north with an elevation of 45. The projectile arcs into the air and then descends, crashing to the ground 600 m downrange 3 s later. With the Sun directly overhead, the projectile's shadow races along the flat stretch of Earth at a fairly constant speed. (a) Compute the instantaneous velocity of the shadow at the moment of impact. (b) What was the average velocity of the shell for the entire flight?


6. An ant, crazed by the Sun on a hot Texas afternoon, darts over an xy plane scratched in the dirt. The x and y components of four consecutive darts are the following, all in centimeters: (30.0, 40.00), (b, -70.0), (-20.0, c), (-80.0, -70.0). The overall displacement of the four darts has the xy components (-140.0, -20). What are (a) component b and (b) component c? What are (c) the magnitude and (d) the angle of overall displacement?


7. A golfer, Roman, takes three putts to get the ball into the hole. The first putt displaces the ball 3.66 m north, the second 1.83 m southeast, and the third 0.91 m southwest. What are (a) the magnitude and (b) the direction of the displacement needed to get the ball into the hole on the first putt?


8. A ship sets out to sail to a point 120 km due north. An unexpected storm blows the ship to a point 100 km due east of its starting point. (a) How far and (b) in what direction must it now sail to reach its original destination?


On to Relative Motion