RI-1A car's hood has a surface area of 2 m2. What is the surface area in cm2? Pink: 200 cm2 Green: 2000 cm2Blue: 20000 cm2= 2104 cm2Yellow: 2105 cm2Purple: None of these.Answer: 2104 cm2. 22 2 2 4 2100 cm2 m 2 100 cm 2 10 cm1 m� ����� = � = ������� �RI-2Consider the equation a x2 + b x = 0. Solve for x.Pink: x = -b/a Yellow: x = a/bGreen: x = ab Blue: x = -abAnswer: Actually, there are two solutions: x = 0 and x = -b/a.RI-3 An object's acceleration vs. time is:Which graph best represents the object's velocity vs. time?Answer: Yellow. Green is not quite correct, because the relative magnitudes of the accelerations (the slopes of v vs.t )are wrong. t a t v t v t v t v Pink Yellow Blue Green Purple: None of these!RI-4 A student is asked the following question on an exam: A car is moving at 90mph and suddenly brakes with a constant acceleration a = –2g to a full stop. How many second does the car take to stop?Which equation can be used to answer the question:21o o2o2 2o oYellow : x x v t a tBlue : v v atGreen : v v 2a(x x ) Answer: Blue.RI-5 At t = 0, a projectile is fired straight upward from a cannon. It goes up and then comes down. Assume that there is no air resistance. Upward is chosen as the positive y-direction. Which of the following graphs most accurately shows velocity vs. time for the projectile during its flight? Answer: Yellow. This is a graph of v = v0 - gt.t v t v Pink Green t v Yellow t v Blue Purple: None of these.RI-6 Consider the vector AWhich equation is correct? Yellow A ABlue A AGreen A APink A Axxxx: cos: cos: sin: sinAnswer: Ax = -A sinRI -7Suppose you know the velocity vector of a particle at a particular instant of time and it is parallel to the ground. What do you know about the acceleration a of the particle?v Pink: The velocity vector and the acceleration vector are always either in the same direction or in opposite directions.Yellow: The acceleration vector is straight down.Green: You know nothing at all about the acceleration vector.Blue: The acceleration must be zero.Answer: You know nothing at all about the acceleration vector. To know the acceleration,you need to know the velocity at two different times. Acceleration is the time rate of change of the velocity.A x yRI-8Consider the vectors V1 and V2 shown. Which is the vector is V = V2 - V1 ?V1 V? V2 Pink Yellow Green Blue Answer: Blue (down). The V has to be in the direction which will satisfy the equation V1+V = V2 , which is equivalent to V = V2 - V1.V V2 V1 RI-9.An elevator is going up at a constant speed. Near the top floor, itstarts to slow to a stop. During the period that it is slowing down,its acceleration isBLUE: downwardYELLOW: upward. PINK: in some other direction.Answer: downward. Can you draw the correct V = V2 - V1 vector diagram to illustrate that the acceleration is down??RI-10The "multiflash photograph" below shows a ball rolling along asurface. The camera flashed once a second, and the time isshown above each image.Which graph below best represents the ball's velocity as afunction of time?Answer: PurpleRI-11What is the direction of vector C A B ?Ax = 1, Ay = 1Bx = -2, By = 2 Correct answer is Blue. Cx = Ax + Bx = +1 - 2 = -1, Cy = Ay + By = +1 + 2 = +3. The vector C points to the upper left, in the second quadrant.xyBlue PinkGreen YellowPurple if along x or y axes.RI-12.A particle is moving with constant acceleration. Its velocity vector at two different times is shown below. What is the direction of the acceleration?Answer: The direction of the acceleration is the same as thedirection of v, which is up. Remember the vector v is thevector you vector-add to vector v1 to get vector v2.xyV1V2BlueYellowGreenPinkPurple: None of these!V1V2gAustralia!v1 v2 vRI-13. Consider the vectors A and B as shown. A has magnitude 2 and B has magnitude 1. What is the direction of the vector (A – 3 B)?A B Pink: Right Yellow: Left Green: No direction because the vector is zero.Answer: RightA is to the right. The vector -3B is also to the right.RI-14. The vector A has length 5. The vector B has magnitude 4. You have no other information about the two vectors. Consider the following statements about the vector A+B.A) The magnitude of the vector A+B can be between 5 and 9.B) The magnitude of the vector A+B can be between 0 and 4.C) The magnitude of the vector A+B can be between -1 and 9.D) The magnitude of the vector A+B can be between 1 and 9.Which statements, if any, are true?Pink: A only Yellow: A and C onlyPink: D only Purple: None of these.Answer: None of these. A and D only. (Note that answer A is a subset of answer D). For a very similar problem. See the CAPA solution to Set 3, problem 11 on the web
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