Browse Momentum

35 questions at your level, grouped by concept

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Linear momentum

16 questions

LessonNot started
  1. 1
    Figure 12 mP (4m kg)Q (3m kg)Diagram not accurately drawn.

    Two particles, PP and QQ, have masses 4m4m kg and 3m3m kg respectively. Initially both particles are stationary on a rough horizontal surface, with PQ=2PQ = 2 m, as shown in Figure 1. The coefficient of friction between each particle and the surface is μ\mu.

    PP is given an impulse of magnitude JJ N s, which sets it moving along the surface towards QQ with speed 5 m s−15\text{ m s}^{-1}
    (a) Find JJ in terms of mm.

    (2 marks)

    When PP reaches QQ, its speed has fallen to 3 m s−13\text{ m s}^{-1}
    (b) Find the value of μ\mu

    (7 marks)

    PP then collides directly with QQ. Immediately after the impact, QQ is moving with speed 3.2 m s−13.2\text{ m s}^{-1}
    (c) Find the speed of PP at this instant.

    (3 marks)
    Level 4 · 12 marksTry it
  2. 2
    A particle of mass 2 kg2\text{ kg} moves in a straight line with velocity v=3t2 m s−1v = 3t^{2}\text{ m s}^{-1} at time tt seconds.
    (a) Find the momentum of the particle when t=2t = 2. (3 marks)
    (b) Find the change in momentum between t=1t = 1 and t=2t = 2. (2 marks)
    Level 4 · 5 marksTry it
  3. 3
    Two ice skaters, of masses 60 kg60\text{ kg} and 75 kg75\text{ kg}, stand at rest facing each other. They push apart, and the lighter skater moves off at 1.5 m s−11.5\text{ m s}^{-1}.
    (a) Find the speed of the heavier skater. (4 marks)
    (b) State the total momentum of the two skaters after they separate, justifying your answer. (1 mark)
    Level 4 · 5 marksTry it

Conservation of linear momentum

19 questions

LessonNot started
  1. 1
    Two particles AA (mass 0.6 kg0.6\text{ kg}) and BB (mass 0.4 kg0.4\text{ kg}) move towards each other on a smooth horizontal surface. AA moves at 5 m s−15\text{ m s}^{-1} and BB moves at 2.5 m s−12.5\text{ m s}^{-1}. They collide and coalesce.
    (a) Find the speed and direction of the combined particle immediately after the collision. (3 marks)
    (b) The combined particle is then brought to rest by a constant resistive force in 0.8 s0.8\text{ s}. Find the deceleration of the particle and the distance it travels before coming to rest. (4 marks)
    Level 4 · 7 marksTry it
  2. 2
    Particle PP (mass 1 kg1\text{ kg}) moves at 6 m s−16\text{ m s}^{-1} towards a stationary particle QQ (mass 2 kg2\text{ kg}). They collide and coalesce; the combined particle then collides with a stationary particle RR (mass 3 kg3\text{ kg}) and all three coalesce.
    (a) Find the speed of the combined particle after the first collision. (3 marks)
    (b) Find the final speed after the second collision. (3 marks)
    Level 4 · 6 marksTry it
  3. 3
    A gun of mass 4 kg4\text{ kg}, initially at rest and free to move, fires a bullet of mass 0.02 kg0.02\text{ kg} horizontally at 300 m s−1300\text{ m s}^{-1}.
    (a) Find the recoil speed of the gun. (3 marks)
    (b) Explain why the total momentum of the system is zero after firing. (1 mark)
    Level 4 · 4 marksTry it