14. Motion Sensor Vo m2 In an experiment, block 1 is given an initial speed vo toward block 2, which is initially at rest. The blocks are on a track that has a motion detector set up, as shown above. When the two blocks collide, there is a completely inelastic collision and the blocks move together with speed Up. The blocks were both placed on a balance, and it is determined that they have the same mass. The experiment is repeated for four different initial speeds, and the data are shown in the chart below. It appears that the resulting data are not accurate. Which measurement most likely produced errors in the data seen in the chart below? Up (m/s) of (m/s) 1 0.42 2 0.85 3 1.33 4 1.70 (A) The mass of block 1 is accurate, but the mass of block 2 is actually less massive than recorded. (B) Both mass values are accurate, but Vo is actually larger than recorded. (C) The motion sensor was positioned too close to block 1 "D) The final velocity recorded was taken too long after the collision. (E) The data recorded is accurate within acceptable experimental error.15. X 6 m/s 530 X O 10 m/s Y Figure I Figure II Two balls are on a frictionless horizontal tabletop. Ball X initially moves at 10 meters per second, as shown in Figure I above. It then collides elastically with identical ball Y, which is initially at rest. After the collision, ball X moves at 6 meters per second along a path at 53" to its original direction, as shown in Figure II above. Which of the following diagrams best represents the motion of ball Y' after the collision?1=0 (A) 10 m/s (B) (C) 370 /370 (D)(E) 8 m/'s 16. An object having an initial momentum that may be represented by the vector above strikes an object that is initially at rest. Which of the following sets of vectors may represent the momenta of the two objects after the collision? (A) (B) (C) (D) (E)17. A student drops a bag of mass m onto a cart of mass Me that is sliding with speed vo along a horizontal track with negligible friction. Immediately after the bag lands in the cart, the cart-bag system moves with speed vy. Which of the following statements correctly relates the two speeds and gives a correct reason for this relationship? (A) of vo, because the kinetic energy of the bag decreases. (D) of > vo, because the linear momentum of the bag is added to the linear momentum of the cart. (E) of = to, because the bag is moving perpendicular to the cart. 18. An arrow of mass m and speed vo strikes and sticks to one end of a meterstick of mass M as shown in the diagram above. The meterstick is initially at rest on a horizontal surface and free to move without friction. The speed of the center of mass of the stick-arrow system after the arrow strikes is given by which of the following expressions? (A) =(M + m)va (B) (D) (E) 019. 4.0 m/s Before Jump After Jump As shown in the figure above, a child of mass 20 kg who is running at a speed of 4.0 m/'s jumps onto a stationary sled of mass 5.0 kg on a frozen lake. The speed at which the child and sled begin to slide across the ice is most nearly (A) 0.20 m/'s (B) 0.80 m/'s (C) 1.2 m/'s (D) 3.2 m/'s (E) 16 m/'s 20. Object 4 of mass M is moving east at speed v. It collides with object B of mass 2MY that was initially at rest. The motion of the objects before and after the collision is along the same line. After the collision, object A is moving west at a speed of w3. What is the speed of object S immediately after the collision? (A) W3 (B) W2 (C) 2w/3 (D) V (E) 2v