Conceptual Questions

Conceptual Questions Overview

• The following questions explore the principles of momentum and impulse, focusing on their relationships and implications in physics.

Page 1

• Q1: Length of force impact affects impulse strength?

  • Yes, impulse depends on both the magnitude of the force and the time it is applied.

• Q2: Two forces with equal impulses, one acting longer?

  • The second force is larger since it acted for a longer time to produce the same impulse.

• Q3: Can a baseball match the momentum of a bowling ball?

  • Yes, due to the formula for momentum (mass × velocity), a high velocity can equal the momentum of a slower and more massive object.

Page 2

• Q4: Are impulse and force the same?

  • No, impulse is the product of force and the time it acts, while force is an instantaneous measure.

• Q5: Are impulse and momentum the same?

  • No, impulse is the change in momentum of an object when a force is applied over time.

• Q6: Ball bounces with same velocity:

  • a. Yes, there’s a change in momentum since the direction changes.

  • b. Yes, impulse is present as the ball interacts with the wall.

• Q7: Advantage of follow-through in baseball hitting?

  • Increases contact time, thus enhancing transfer of momentum.

• Q8: Padded vs. rigid dashboard for injury reduction?

  • Padded dashboards extend the time over which momentum change occurs, reducing force and potential injuries.

• Q9: Airbag effectiveness in collisions?

  • Increases time for momentum change, allowing a lower force on the passenger, resulting in less severe injuries.

• Q10: Airbags inflating too rapidly?

  • Could cause higher forces if the airbag compresses too quickly in low-velocity scenarios.

• Q11: Catching a ball with pulled-back arm?

  • Yes, pulling back reduces the average force experienced by the hand.

Page 3

• Q12: Moving hand forward for egg toss?

  • Moving forward reduces the impact and likelihood of breaking the egg as it extends the time to come to rest.

• Q13: Truck vs. bicycle with same velocity - which needs larger impulse?

  • The truck requires a larger impulse due to its larger mass.

• Q14: Conservation of momentum - always valid?

  • Not always; it requires no external forces for valid application.

• Q15: Is momentum conserved when a ball rolls down an incline?

  • No, momentum isn't conserved due to net forces acting on it (gravity).

• Q16: Momentum conservation in colliding objects?

  • Momentum is conserved for the entire system even though individual momentums may not be.

• Q17: Which of Newton’s laws support momentum conservation?

  • Newton’s third law (action-reaction) plays a crucial role in momentum conservation during collisions.

• Q18: Head-on collision:

  • a. Equal force of impact on both vehicles (Newton’s third law).

  • b. Equal impulse (same time duration of impact).

  • c. Greater change in momentum for larger vehicle due to greater mass.

  • d. Greater acceleration for the lighter vehicle due to F=ma.

• Q19: Fullback vs. defensive back collision?

  • Yes, if they become entangled, momentum can cause the fullback to move backward.

Page 4

• Q20: Two skaters push off each other - total momentum?

  • Total momentum remains zero, as they propel equally opposite to each other.

• Q21: Recoil of two shotguns?

  • Both recoil with the same momentum; lighter one has a greater velocity post-fire.

• Q22: Momentum conservation in cannon on a boat?

  • Yes, momentum is conserved if considering the system of the cannon and the boat.

• Q23: Can a rocket function in a vacuum?

  • Yes, by expelling mass in one direction, it moves in the opposite direction due to momentum conservation.

• Q24: Getting moving on a slick surface with oranges?

  • Throwing the oranges backward results in momentum gained forward due to conservation principles.

• Q25: Astronaut drifting in space - how to move?

  • By throwing tools in the opposite direction, the astronaut gains momentum back towards the station.

• Q26: Sailboat fan for propulsion?

  • The fan changes momentum of the air, creating a reaction force that propels the boat forward.

Page 5

• Q27: Skateboard with jumping person - speed change?

  • The skateboard slows down as the total mass increases, maintaining momentum.

• Q28: Collision of rail cars - velocity after collision?

  • Less than the first car’s velocity due to mass increase.

• Q29: Collision type of rail cars?

  • Partially inelastic since they couple and conserve momentum without rebounding.

• Q30: Conservation in collisions - is it elastic?

  • Not necessarily; momentum can be conserved in inelastic collisions as well.

• Q31: Ball bounces off wall - collision type?

  • Not elastic if energy is lost in the process and velocity decreases.

Page 6

• Q32: Ball bounces off wall - momentum conservation?

  • a. Ball’s momentum isn't conserved due to wall interaction.

  • b. Total system momentum isn't conserved if including Earth as part of the system.

• Q33: Cue ball hitting stationary 8-ball - elastic collision?

  • Yes, momentum and kinetic energy are conserved in this type of collision.

• Q34: Colliding clay lumps - vector addition?

  • Momentum vectors combine, providing a resultant vector scaled to the combined mass.

• Q35: Right-angle clay collision and sticking together?

  • Yes, the combined mass leads to a resultant vector defined by Pythagorean theorem.

Page 7

• Q36: Cars collide at right angles - greater prior velocity?

  • The car with the greater post-collision angle had the larger pre-collision velocity.

• Q37: Car and truck collision vector?

  • The momentum vector system should be skewed towards the heavier truck due to its mass.

• Q38: Cue ball glancing blow sketch?

  • Visual representation needed showing momentum before and after collision, indicating their vector changes.