25. A toy spacecra is launched directly upward. When the toy reaches its highest point, a spring is released and the toy,r splits into two parts with masses of 0.02 kg and 0.08 kg, respectively. Immediater aer the separation, the 0.02 kg part moves horizontally due east. Air resistance is negligible. True statements about the 0.08 kg part include which of the following? I. It could move north immediately after the spring is released. II. It takes longer to reach the ground than does the 0.02 kg part. III. It strikes the ground farther from the launch point than does the 0.02 kg part. (A) None V (B) I only (C) III only (D) I and 11 only (E) II and III only 21. A toy cannon is fixed to a small cart and both move to the right with speed v along a straight track, as shown above. The cannon points in the direction of motion. When the cannon res a projectile the cart and cannon are brought to rest. if M is the mass of the cart and cannon combined without the projectile. and m is the mass ot'the projectile, what is the speed of the projectile relative to the ground immediately after it is fired? AP Physics C: Mechanics Page 13 of 22 m swim: Unit 4.3 Conservation of Momentum and Collisions 22. .lI ,- (A) Vi (B) lilignjur \\/ ill! 1 4' r: (C) ) mt! (D) (M: mi'.' (E) (31717:) A railroad car of mass 1500 kg rolls to the right at 4 We and collides with another railroad car of mass 3000 kg that is rolling to the left at 3 mfs. The cars stick together. Their speed immediately aer the collision is (A) m \\x (B) lrnls (C) gm (D) $1M (E) 7 m/s 23. Uo m An object of mass m is moving with speed vo to the right on a horizontal frictionless surface, as shown above, when it explodes into two pieces. Subsequently, one piece of mass i'm moves with a speed -2 to the left. The speed of the other piece of the object is (A) 2 (B) (C) 5 (D) 3vo 2 (E) Page 14 of 22 AP Physics C: Mechanics AP CollegeBoard Scoring Guide Unit 4.3 Conservation of Momentum and Collisions 24. 3 m/s 2 m/s 2 m/s 3 m/s Before Collision After Collision Object X of mass m is moving to the right with a speed of 3 m/s when it collides with object Y of mass m that is moving to the right with a speed of 2 m/s, as shown above. After the collision, X is moving to the right with a speed of 2 m/s and Y is moving to the right with a speed of 3 m/s. Which of the following is true of the collision? (A) It is elastic because momentum is conserved. B) It is elastic because kinetic energy is conserved. C) It is inelastic because momentum is not conserved. (D) It is inelastic because kinetic energy is not conserved. More information is needed to determine whether the collision is elastic or inelastic