Topic 4 - Momentum, Energy, Work And Power Flashcards
What happens to the velocity of an object if the mass of the object is great?
The greater its mass, the greater its velocity
What affects your total stopping distance?
Thinking distance (reaction time and your speed)
Braking distance (your speed, mass of vehicle, how good your brakes are and how good the grip is)
Is momentum a vector quality?
YES! It has a size and direction
Do forces cause change in momentum?
YES! A larger force means a faster momentum (and so a greater acceleration).
What protective features are on a car?
Crumple zone - increases time taken for car to stop
Seat belts - increasing the time for wearer to stop which reduces forces on the chest
Air bags - slows you down more gradually
When a force moves an object, what happens to the energy and work?
When a force moves an object, energy is transferred and work is done
What is kinetic energy?
The energy of movement
What does kinetic energy depend on?
Mass and velocity
What is gravitational potential?
Energy due to height
What is GPE measured in?
N/kg
State the principle of the conservation of energy?
Energy can not be created or destroyed - only transferred
Energy is only useful when it is transferred from one form to another
What effects Reaction time
Alcohol intake - slows down (depressant) Medicines How fast you're going Tiredness Fog/Visibility
What effects breaking distance
Grip on the tyres
Mass and velocity of vehicle
How good the brakes are
Weather - slippery surfaces
What comes into your stopping distance
First = thinking time Second = breaking time
Unit of momentum
Kg m/s
