SAT Mechanics B - Energy and Momentum

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1. Which of these expressions is the rate of change of momentum?
  • A) Δp
  • B) m/t
  • C) Δm/t
  • D) Δp/Δt
  • E) p/t
2. One of Newtons laws of motion states that the rate of change of momentum is equal to
  • A) Acceleration
  • B) Force
  • C) Mass
  • D) Velocity
  • E) Impulse
3. A firework rocket accelerates for the first few seconds and gains height above the ground. Which of the following best describes the energy changes taking place at this point?
  • A) chemical and potential converted to kinetic
  • B) kinetic converted to chemical and potential
  • C) chemical converted to potential and kinetic
  • D) potential converted to kinetic and chemical
  • E) potential and kinetic converted to chemical
4. The graph shows the force required to stretch a steel cable. What work has been done stretching the cable by 12 cm?
  • A) 240 J
  • B) 120 J
  • C) 2.4 J
  • D) 2.0 J
  • E) 1.2 J
5. Momentum is defined as ..
  • A) the product of mass and velocity
  • B) the force required to stop an 1kg object travelling at 1ms-1
  • C) the speed of an object multiplied by the distance traveled
  • D) the rate of change of force
  • E) the rate of change of velocity

6. A small steel ball of mass m is fired at a solid wall at a speed v. It rebounds at a speed of v/2.

The total momentum change is

  • A) 3mv/2
  • B) mv/2
  • C) 2mv
  • D) 2mv/3
  • E) mv
7. An inelastic collision is one in which..
  • A) the final velocity is less than the impact velocity
  • B) momentum is not conserved
  • C) kinetic energy is not conserved
  • D) the final average velocity is less than the initial average velocity
  • E) the momentum is conserved but the kinetic energy increases
8. A 20g bullet hits a 40g stationary block of wood at 60 m/s and remains embedded in the wood. What is the final velocity of block and bullet?
  • A) 40 m/s
  • B) 30 m/s
  • C) 25 m/s
  • D) 20 m/s
  • E) 10 m/s

9. A 0.2kg tennis ball is hit at 20 m/s. Which answer gives the correct values for momentum and kinetic energy?

  Momentum (kgm/s) k.e. (J)
A. 40 40
B. 4 200
C. 40 80
D. 40 20
E. 4 40
10. Estimate the impulse on the tennis ball as it is struck using information from this graph.
  • A) 16 Ns
  • B) 16 kNs
  • C) 32 Ns
  • D) 32 kNs
  • E) 160 Ns