Allen High School

• PHYSICS physics

• 2011-2012 Physics I Exam Review- 2nd Semester Momentum/Impulse/Collisions __B__ 1. An ice skater initially skating at a velocity of 3 m/s speeds up to a velocity of 5 m/s. The momentum of the skater ________. a. decreases c. remains the same b. increases d. becomes zero __C__ 2. If a force is exerted on an object, which statement is true? a. A large force always produces a large change in the object’s momentum. b. A large force produces a large change in the object’s momentum only if the force is applied over a very short time interval. c. A small force applied over a long time interval can produce a large change in the object’s momentum. d. A small force produces a large change in the object’s momentum. __C__ 3. A constant impulse is applied to stop a moving shopping cart. Increasing the time interval over which the force is applied means that the stopping force is ________. a. greater c. smaller b. unaffected d. the same __D__ 4. A 0.06 kg tennis ball moves at a velocity of 12 m/s. The ball is struck by a racket, causing it to rebound in the opposite direction at a speed of 18 m/s. What is the change in the ball’s momentum? a. –0.38 kgm/s c. –1.1 kgm/s b. –0.72 kgm/s d. –1.8 kgm/s Diagram: (Given + Unknowns) m = .06 kg vf = -18 m/s vi = 12 m/s Equation: impulse = m (vf – vi) Substitute: impulse = m (vf – vi) Impulse = (.06kg)( -18 m/s - 12m/s) = - 1.8 kg m/s Solve: Impulse = - 1.8 kg m/s _C___ 5. The impulse experienced by a body is equivalent to the body’s change in ________. a. velocity c. momentum b. kinetic energy d. force _C___ 6. Which of the following are possible units for impulse? a. kg m/s c. Both A and B b. N s d. Neither A nor B _B___ 7. A 75 kg person walking around a corner bumps into an 80 kg person running around the same corner. The momentum of the 80 kg person ________. a. increases c. remains the same b. decreases d. is conserved __A__ 8. Two objects move separately after colliding, and both the total momentum and total kinetic energy remain constant