momentum

• What is momentum?

  A property of all moving objects
• How is momentum calculated?

  Momentum is mass times velocity
• What is the equation for momentum?

  p = mv
• What are the units of momentum?

  kilogram metre per second (kg m/s)
• What happens to the momentum of an object at rest?

  It has no momentum
• How does momentum affect an object's direction?

  It keeps the object moving in the same direction
• What is the effect of large momentum on direction change?

  It is difficult to change the direction
• What type of quantity is velocity?

  A vector with magnitude and direction
• How can momentum be positive or negative?

  Depends on the direction of travel
• What direction is usually considered positive in momentum questions?

  To the right
• How does the momentum of a ball change after a collision?

  It changes direction and sign

  
• What factors can change the momentum of an object?

  Changes in velocity, direction, or mass
• How do you calculate the momentum of a tennis ball with mass 0.06 kg and velocity 75 m/s?

  $p =$$0.06 \times 75 =$$4.5 \text{ kg m/s}$
• How do you calculate the momentum of a brick with mass 3 kg and velocity 1.5 m/s?

  $p =$$3 \times 1.5 =$$4.5 \text{ kg m/s}$

  
• Why do the tennis ball and brick have the same momentum despite different masses?

  The ball travels faster than the brick

  
• What does the principle of conservation of momentum state?

  Total momentum before equals after interaction
• What types of interactions can momentum conservation apply to?

  Collisions and explosions
• What happens to momentum in a collision between two objects?

  Total momentum before equals total after
• How is momentum calculated before a collision?

  Only the moving object's momentum counts
• What is the total momentum of a system moving in opposite directions at the same speed?

  Overall momentum is zero
• How do you calculate the total momentum before a collision of a car moving at 10 m/s with mass 990 kg?

  $p =$$990 \times 10 =$$9900 \text{ kg m/s}$

  
• How do you calculate the total momentum after a collision for a car with mass 990 kg moving at 2 m/s?

  $p =$$990 \times 2 =$$1980 \text{ kg m/s}$

  
• How do you find the velocity of the van after a collision?

  Use conservation of momentum equation

  
• What is the formula for resultant force?

  F = change in momentum over time
• What does a negative force indicate in momentum problems?

  Direction is opposite to initial motion

  
• What is Newton's third law of motion?

  Forces are equal and opposite in interaction

  
• How does Newton's third law apply to walking?

  The foot pushes down, ground pushes up

  
• What is the formula for momentum?

  Momentum = mass × initial velocity
• How is final momentum expressed?

  Final momentum = mass × final velocity
• What does the equation \( F = mv - mu \) represent?

  It represents the change in momentum over time
• If a car has a mass of 1500 kg and an initial velocity of 15 m/s, what is the initial momentum?

  $22500 \text{ kg m/s}$
• What is the force calculated when the final momentum is -7500 kg m/s and initial momentum is 22500 kg m/s over 3 seconds?

  $-10000 \text{ N}$
• What does the negative sign in the force indicate?

  The force direction is to the left
• What is Newton's third law of motion?

  Forces between two objects are equal and opposite

  
• How does Newton's third law explain walking?

  The foot pushes the ground backwards

  
• What are the three rules to identify a third law pair?

  Different objects, equal size, same type
• What are the forces acting on a book at rest on a table?

  • Weight (downward force)
  • Normal contact force (upward force)

  
• Why is Student B correct in the example of the book on the table?

  The forces act on different objects

  
• What happens when two objects collide according to Newton's third law?

  Both objects will react with equal forces

  
• How does acceleration relate to force and mass?

  Acceleration depends on force and mass