CHAPTER 3 TEST REVIEW Answer Key

Transcription

1 PRE-DP PHYSICS Name: DEVIL PHYSICS Period: Date: # Marks: XX Raw Score: IB Curve: BADDEST CLASS ON CAMPUS 1. State the difference between a vector and a scalar CHAPTER 3 TEST REVIEW Answer Key A scalar can be described with just a magnitude while a vector must be described by both a magnitude and direction. 2. What is meant by the term components of a vector? Two vectors, usually aligned with horizontal (x) and vertical (y) axes whose sum is the original vector. Vectors are broken down into components with common alignment so they can be added or subtracted. 3. What is a resultant vector? The answer to a vector addition or subtraction problem. 4. Name two methods for graphically adding two vectors. Tail-to-tip method and parallelogram method. 5. How do you subtract vectors? Add the directional inverse of the vector you are subtracting. 6. Describe how you would find the components of a vector if you knew its magnitude and direction. Place the origin of a set of coordinate axes at the tail of the vector. Draw vectors parallel to the axes that form a right triangle with the vector as the hypotenuse. The sum of these component vectors is the vector in question. Use sine and cosine to find the value of the component vectors. 7. List the four steps in the problem solving process for projectile motion. 1. Choose an origin and an xy coordinate system. 2. Analyze the horizontal (x) and vertical (y) motion separately. 3. List the known and unknown quantities. 4. Apply releveant equations. 8. What type of path is followed by an object in projectile motion. What is the equation of the graph of this motion?

2 parabolic, y = ax + bx 2 9. Why do we study relative velocity? In order to consider how observations made in different reference frames are related to one another. 10. Graphically add the following three vectors: 11. Graphically show the resultant for A B. ( 2 / ) A B R B A ( 2 / ) 12. What is the cosine of 57?

3 13. What is the tangent of For the triangle in Figure 1, if a = 43 and x = 27m, give the value of the following: b = 180 b = 47 y: y: y: y: z: z: z: z: 15. For the triangle in Figure 1, if z = 78in and x = 96in, give the value of the following: z a Figure 1 y x b ( 3 / ) a: a: a: a: b: b: b: b: ( 3 / ) 16. Vector P has a magnitude of 39 and lies 29 below the negative x axis. Give the x- and y- components for. P x 29 Px: Px: Px: Px: Py: Py: Py: Py: P y

4 17. If and, give the magnitude of and state the direction of in relation to the x-axis. W W y =27in W x =15in ( 2 / ) 18. Using the vectors in Figure 2, give the magnitude and direction of. Ax: Ax: Ax: Ax: Ay: Ay: Ay: Ay: Figure 2

5 ( 5 / ) 19. Using the vectors in Figure 2, give the magnitude and direction of. Bx: Bx: Bx: Bx: By: By: By: By: ( 5 / ) 20. A bowling ball rolling at 2.80 m/s rolls off the end of a table that is 3m high a. How long does it take for the bowling ball to hit the floor?

6 b. How far from the end of the table will the bowling ball hit the floor? c. What is the magnitude and direction of the bowling ball s velocity just prior to hitting the floor?

7 ( 7 / ) 21. A basketball is rolled off the top of a building at 3.7 m/s. It hits the ground 17 meters from the side of the building. How tall is the building 103.8m ( 3 / ) 22. A catapult launches a boulder at a 64 degree angle toward a castle. The boulder clears the castle wall and lands in the courtyard. If the boulder was launched at 7.8 m/s, a. H ow far away was the boulder s impact from the catapult? v 0 = 7.8m/s v yo 64 v xo b. W hat is the maximum height of the castle wall?

8 The vertical velocity is zero at the highest point of the parabola ( 4 / ) 23. Ray Guy was a Hall of Fame punter for the Oakland Raiders. He could punt a football 40 meters with a hang time (time the ball was airborne) of 4.5 seconds. What was the velocity and angle of that punt in relation to the field?

9 ( 4 / ) 24. While driving the mighty rocket Nissan Frontier down 5 th avenue the other day, I noticed the rain was going by my side window at a pretty steep angle which seemed interesting because at the last stoplight it was coming straight down. I whipped out the protractor I always leave in my shirt pocket and measured the angle to be 38.7 from the vertical. At the time, I was driving 27 m/s. What is the velocity of the rain with respect to the car and to the ground? v RC =? m/s = 38.7 v CG = 27 m/s v RG =? m/s 25. A boat is pointed directly across a river that is 120m wide and has a current that flows at 2.25 m/s. There is a dam located 50m downstream. What is the minimum speed the boat must travel to get across the river without going over the dam? ( 3 / ) x = 50 m v WS = 2.25 m/s v BW =? m/s y = 120 m