Further Motion concepts

• What is the equation for momentum?

  momentum = mass × velocity ; p = mv
• How does momentum depend on mass and velocity?

  Momentum increases with mass and velocity; more mass or higher speed = greater momentum.
• What is the unit of momentum?

  kg·m/s
• What does Newton's second law tell us about force and momentum?

  Force is the rate of change of momentum.
• What is the law of conservation of momentum?

  Total momentum before an interaction = total momentum after, if no external forces act.
• How does Newton's third law relate to conservation of momentum?

  Action and reaction forces are equal and opposite, so momentum is conserved in interactions.
• What is the equation for kinetic energy?

  KE = ½mv²
• When is kinetic energy conserved in a collision?

  In elastic collisions (perfectly bouncy).
• When is kinetic energy not conserved in a collision?

  In inelastic collisions (objects stick together or deform).
• What is the SUVAT equation linking v, u, a, and t?

  v = u + at
• What is the SUVAT equation linking x, u, v, and t?

  x = ½(u + v)t
• What is the SUVAT equation linking x, u, a, and t?

  x = ut + ½at²
• What is the SUVAT equation linking v, u, a, and x?

  v² = u² + 2ax
• What does the principle of moments state?

  For a system in equilibrium, total clockwise moment = total anticlockwise moment.
• What is the equation for a moment?

  Moment = Force × perpendicular distance ; M = Fd
• What are the units of a moment?

  Newton metres (Nm)
• Give an example of a situation involving rotational forces.

  Opening a door, using a wrench, seesaw.
• What increases the size of a moment?

  Larger force or longer perpendicular distance from pivot.
• In a balanced metre rule with weights, what must be true?

  The total clockwise and anticlockwise moments must be equal.