Grade 10 Exam  >  Grade 10 Notes  >  Physics for Grade 10  >  Momentum & Safety

Momentum & Safety | Physics for Grade 10 PDF Download

Introduction

  • Since force is equal to the rate of change in momentum, the force of an impact in a vehicle collision can be decreased by increasing the contact time over which the collision occurs
    • The contact time is the time in which the person is in contact with what they have collided with
  • Therefore, safety features are created to reduce the impact of a force, such as in:
    • Vehicles
    • Playgrounds
    • Bicycle helmets
    • Gymnasium crashmats

Vehicles

  • Vehicle safety features are designed to absorb energy upon an impact by changing shape
  • The main vehicle safety features are crumple zones, seat belts and airbags
    • For a given force upon impact, these absorb the energy from the impact and increase the time over which the force takes place
    • This, in turn, increases the time taken for the change in momentum of the passenger and the vehicle to come to rest
    • The increased time reduces the force and risk of injury on a passenger
  • The usefulness of safety equipment depends on two main factors: mass and velocity
  • If the impact is from a large mass, for example, a truck travelling very fast and colliding with a wall, the momentum will be very large
    • The change in momentum (ie. from a high speed to rest) will also be very large
    • This means that a very long contact time is needed to reduce the force of impact
      The seat belt, airbag and crumple zones help reduce the risk of injury on a passenger
      The seat belt, airbag and crumple zones help reduce the risk of injury on a passenger

Seat belts

  • These are designed to stop a passenger from colliding with the interior of a vehicle by keeping them fixed to their seat in an abrupt stop
  • They are designed to stretch slightly to increase the time for the passenger’s momentum to reach zero and reduce the force on them in a collision

Airbags

  • These are deployed at the front on the dashboard and steering wheel when a collision occurs
  • They act as a soft cushion to prevent injury on the passenger when they are thrown forward upon impact

Crumple zones

  • These are designed into the exterior of vehicles
  • They are at the front and back and are designed to crush or crumple in a controlled way in a collision
  • This is why vehicles after a collision look more heavily damaged than expected, even for relatively small collisions
  • The crumple zones increase the time over which the vehicle comes to rest, lowering the impact force on the passengers

Crash Mats

  • Crash mats used in gymnasiums help reduce the risk of injury for falls in gymnastics and climbing
    • They are thick and soft to offer shock absorption of the force created by the person landing on the mat
  • When a person lands on a crash mat with a large force, for example after jumping, the soft landing means their body is in contact with the mat for a longer period of time than if it was otherwise not there
  • This increases the contact time over which their momentum is reduced creating a smaller impact force and a lower chance of injury
    A bouldering mat is a type of crash mat used to reduce the chance of injury in falls whilst climbing
    A bouldering mat is a type of crash mat used to reduce the chance of injury in falls whilst climbing
  • In a similar way, playgrounds utilise cushioned surfaces as children will often fall onto these with a large force
    • The cushioned surface reduces the risk of a severe injury by increasing their contact time with the ground
  • Meanwhile, a child in a gymnasium can use a thinner crash mat than an adult due to having a lower mass
  • This is the same for activities where a person/adult will fall with a low velocity such as falling from lower heights
    • Therefore, thin crash mats are suitable for low-impact activities
  • Safety features are intended to reduce the chance of serious injury but do not completely prevent it in all cases
The document Momentum & Safety | Physics for Grade 10 is a part of the Grade 10 Course Physics for Grade 10.
All you need of Grade 10 at this link: Grade 10
124 videos|149 docs|37 tests

Top Courses for Grade 10

124 videos|149 docs|37 tests
Download as PDF
Explore Courses for Grade 10 exam

Top Courses for Grade 10

Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Related Searches

mock tests for examination

,

Momentum & Safety | Physics for Grade 10

,

Viva Questions

,

study material

,

Exam

,

Semester Notes

,

Previous Year Questions with Solutions

,

Momentum & Safety | Physics for Grade 10

,

ppt

,

past year papers

,

Summary

,

MCQs

,

Extra Questions

,

practice quizzes

,

Free

,

pdf

,

Momentum & Safety | Physics for Grade 10

,

video lectures

,

Sample Paper

,

shortcuts and tricks

,

Important questions

,

Objective type Questions

;