Momentum - AP Physics 1

1. How does momentum change if mass doubles and velocity stays constant?

   Momentum doubles. Momentum is directly proportional to mass.

2. What is conserved in an elastic collision?

   Both momentum and kinetic energy. These are the two conserved quantities in elastic collisions.

3. How does friction affect momentum in a system?

   Friction can reduce momentum. Friction is an external force that affects momentum.

4. Calculate momentum for a 0.5 kg ball traveling at 10 m/s.

   $p = 5$ kg·m/s. Using $p = mv = 0.5×10 = 5$ kg·m/s.

5. Find momentum if mass is 7 kg and velocity is 3 m/s.

   $p = 21$ kg·m/s. Using $p = mv = 7×3 = 21$ kg·m/s.

6. Which has more momentum: a 5 kg object at 2 m/s or a 10 kg object at 1 m/s?

   Both have 10 kg·m/s of momentum. Both equal $5×2 = 10$ and $10×1 = 10$ kg·m/s.

7. How does momentum change if velocity doubles and mass stays constant?

   Momentum doubles. Momentum is directly proportional to velocity.

8. Calculate the momentum of a 3 kg object traveling at 4 m/s.

   $p = 12$ kg·m/s. Using $p = mv = 3×4 = 12$ kg·m/s.

9. What is the impulse if a force of 6 N acts for 3 s?

   $J = 18$ Ns. Using $J = F×\Delta t = 6×3 = 18$ Ns.

10. If momentum is 20 kg·m/s and velocity is 4 m/s, find the mass.

    $m = 5$ kg. Rearranging $p = mv$ gives $m = p/v = 20/4$.

11. Calculate the impulse if a force of 8 N acts for 3 s.

    $J = 24$ Ns. Using $J = F×\Delta t = 8×3 = 24$ Ns.

12. Identify the variable for momentum in equations.

    Momentum is represented by $p$. Standard physics notation for momentum.

13. What is the momentum of a 10 kg object moving at 0 m/s?

    0 kg·m/s. Zero velocity results in zero momentum.

14. What happens to momentum in a perfectly inelastic collision?

    Objects stick together, total momentum conserved. The most inelastic case where objects combine.

15. If a 2 kg ball rolls at 1 m/s, what impulse stops it in 2 s?

    -2 Ns. Initial momentum is $2×1 = 2$ kg·m/s, final is 0.

16. Define momentum.

    Momentum is the product of mass and velocity. This definition follows directly from $p = mv$.

17. State the impulse-momentum theorem formula.

    $\text{Impulse} = \text{Change in momentum}$. This theorem connects impulse to momentum change.

18. Identify the variable representing impulse.

    Impulse is represented by $J$. Standard physics notation for impulse.

19. Calculate the force exerted if a 10 Ns impulse acts over 2 seconds.

    $F = 5$ N. Rearranging $J = F×\Delta t$ gives $F = J/\Delta t = 10/2$.

20. What is the momentum of a 2 kg object at rest?

    0 kg·m/s. Zero velocity means zero momentum regardless of mass.

21. What is the formula for impulse?

    $J = F \times \triangle t$. Force multiplied by time interval gives impulse.

22. If impulse is 15 Ns and time is 5 s, find the force.

    $F = 3$ N. Rearranging $J = F×\Delta t$ gives $F = J/\Delta t = 15/5$.

23. What is the formula for momentum?

    $p = mv$. This is the fundamental equation defining momentum.

24. What is the change in momentum called?

    Impulse. Impulse is defined as the change in momentum.

25. State the relationship between force and change in momentum.

    Force equals the rate of change of momentum. This is Newton's second law in momentum form.

26. What are the units of momentum?

    Kilogram meter per second (kg·m/s). Derived from mass (kg) times velocity (m/s).

27. What is the effect on momentum if mass is halved and velocity is doubled?

    Momentum stays the same. The mass and velocity changes cancel out.

28. Find the velocity if momentum is 30 kg·m/s and mass is 5 kg.

    $v = 6$ m/s. Rearranging $p = mv$ gives $v = p/m = 30/5$.

29. What is the resulting force if a 15 Ns impulse occurs over 3 s?

    $F = 5$ N. Rearranging $J = F×\Delta t$ gives $F = J/\Delta t = 15/3$.

30. State the law of conservation of momentum.

    Total momentum remains constant in an isolated system. This applies when no external forces act on the system.

31. Determine the impulse needed to stop a 5 kg object moving at 4 m/s.

    -20 Ns. Final momentum is 0, initial is $5×4 = 20$ kg·m/s.

32. Calculate momentum for a 4 kg object at 5 m/s.

    $p = 20$ kg·m/s. Using $p = mv = 4×5 = 20$ kg·m/s.

33. If velocity triples and mass is constant, what happens to momentum?

    Momentum triples. Momentum is directly proportional to velocity.

34. If a system has two objects at rest, what is the total momentum?

    0 kg·m/s. Rest means zero velocity for both objects.

35. State the unit for impulse.

    Newton second (Ns). Newton second is equivalent to kg·m/s.

36. Determine the change in momentum for a 4 kg object increasing speed from 2 m/s to 5 m/s.

    12 kg·m/s. Change is $4×5 - 4×2 = 20 - 8 = 12$ kg·m/s.

37. What is the momentum change if a 3 kg object accelerates from 0 to 3 m/s?

    9 kg·m/s. Change is $3×3 - 3×0 = 9$ kg·m/s.

38. How is momentum conserved in a closed system?

    Total momentum before and after is equal. Conservation requires no external forces acting.

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